Page ·arno ~a 2 Nature’s Vagaries: The Weather of 1995 and the Living Volume 55 Number 4 1995-1996 Collections of the Arnold Arboretum Todd Forrest Arnoldia (ISBN 004-2633; USPS 866-100) is 166 Hardy Asian Alders published quarterly by the Arnold Arboretum of Kim E. Tripp Harvard Umversity. Second-class postage paid at Boston, Massachusetts. 26 A Nitrogen Fixation: The Story of the Frankia Symbiosis Subscriptions are $20.00 per calendar year domestic, Peter Del Tredici $25.00 foreign, payable m advance. Smgle copies are $5.00. All remittances must be m U.S. dollars, by 32 The Year in Trees and Words: check drawn on a U.S. bank, or by mternational Book Note and Excerpt money order. Send orders, remittances, change-of- A of address notices, and all other subscription-related 34 Celebration Crabapples: commumcations to: Circulation Manager, Arnoldia, Book Review The Arnold Arboretum, 125 Arborway, Jamaica Plam, O’ .~. Richard Schulhof MA 02130-3519. Telephone 617/524-1718 36 Arnold Arboretum Weather Station Data-1995 Postmaster: Send address changes to Arnoldia 37 Index to Arnoldia, Volume 55 The Arnold Arboretum 125 Arborway Front cover: Birches encased in ice on the lower Jamaica Plam, MA 02130-3519 slopes of Bussey Hill, March 1995. Photo by Peter Del Tredici. Karen Madsen, Editor Inside cover: Bussey Brook valley after the ice March Kim E. Editonal Committee storm, 1995. Photo by Tnpp. Phyllis Andersen Robert E. Cook Peter Del Tredici Gary Koller Richard Schulhof Stephen A. Spongberg

Arnoldia is set m Trump Mediaeval typeface.

Copyright © 1995 The President and Fellows of Harvard College

Corylus avellana ’Contorta’

Nature’s Vagaries: The Weather of 1995 and the Living Collections of the Arnold Arboretum

Todd Forrest

° The result of 1995’s ice storm and drought will probably be the decline - * of many Arboretum plants, but it’s all part of the institution’s mission to determine the hardiness of native and exotic species.

In early August 1995, as meteorologists in few mature plants are watered or fertilized. Boston crowed about six straight weekends of While more than 120 years of this management perfect beach weather, the leaves of Magnolia policy has enabled Arboretum horticulturists to macrophylla, Arnold Arboretum accession determine the hardiness of many exotic species, 1041-70-D, were turning crisp around the edges the knowledge has often come at the expense of and rolling inward. By mid-August, after two individual plants in the collections. Favorite more weeks of hot, sunny days, the plant’s des- specimens break up in storms, mass plantings iccated brown leaves littered the ground on the succumb to drought and disease, and tender spe- gentle, east-facing slope by Centre Street. In cies freeze in colder than average winters. ? mid-September, after nearly forty days without With an eye to monitoring plant hardiness, appreciable rain, most of the young trees and the Arnold Arboretum’s staff has always com- shrubs planted in the spring had dropped their piled data on the weather. During the early foliage, the largest specimens of Clethra years the curator kept records of severe weather almfolia were wilted, and the entire collection indirectly through the plants file. If a specimen of Rhododendron calendulaceum looked like it was killed by an early or late frost, suffered had been torched. When it finally did rain on storm damage, or died in a drought, he recorded September 17, the ground was so hard and dry this information on an index card with the that most of the rainwater ran off immediately plant’s accession number, its location on the and an already scaled-down fall planting was grounds, and the date of the field check. When postponed until October. Arboretum director Charles Sargent or plant re- Although this injury disturbs the Arnold corder J. G. Jack wanted to know what range of Arboretum’s staff and visitors, it is in fact an temperature a given species could withstand, inevitable result of the horticultural Darwinism they scanned the records of all the individual central to the institution’s mission as a place for plants of that taxon and checked for patterns in plant research. The Arboretum’s grounds are an their survival rates. Sargent and Jack used these outdoor laboratory where woody plants from data for their "Notes From the Arnold Arbore- around the world are tested for their ability to tum" column in Garden and Forest-a source of survive the New England climate. In order to some of the earliest observations of ornamental facilitate this research, the Arboretum follows a plant hardiness in American horticulture.’ conservative approach to plant maintenance. To supplement the indirect weather records The vast majority of trees and shrubs are pruned kept in the plants file, the greenhouse staff has only to remove dead or diseased wood and very also kept a log of temperature and precipitation.

The drought lastmg from February to September was not the only weather record set m 1995. This photo, taken m early December, shows a cedar of Lebanon (Cedrus libani~ after one of the storms that helped break the record for the most snowfall before the official start of wmter on 21 December 4-,

Seven microchmates, descmbed below, are indicated on this map of the Arnold Arboretum.

From 1918 to 1946 propagator William Judd 4) a protected area on an east-facing slope recorded daily maximum and minimum tem- along Centre Street, now known as the peratures and made brief notes about precipita- Centre Street bank tion and cloud cover. His entries were simple: 5) a flat spot in the valley where Bussey he his comments to the and fit his kept point Brook and a spring converge observations onto a single line in a small note- a cove amidst the mature book. For example, on 21 September 1938, the 6) protected hemlocks on Hemlock Hill day of the most destructive storm in Arboretum history, Judd noted that the minimum and 7) a plateau near the old site of the Bussey . maximum temperatures were 61 and 80 degrees Institution on South Street and commented F, respectively, simply, "rain, Each of these seven zones shows differences terrific hurricane. "2 in average minimum temperatures (from 10.9 to In 1934 set thermom- ecologist Hugh Raup up 15.9 degrees F) caused by factors such as expo- eters and rain gauges in different sections eight sure and air drainage. Using this information, of the Arboretum. His data, interpreted by Raup and later Fordham concluded that the Alfred Fordham in a 1970 issue of Arnoldia, Centre Street bank-area number 4-because of describe seven microclimates within the Arbo- its warmth in the winter and its protection from retum. (The set up on Peters Hill equipment sun and wind, has the microclimate most favor- was stolen one month after the project started.)( able for marginally hardy specimens.3 Subse- 1) the slope on the southwestern side of quent horticulturists have used Raup’s data to the Administration building, across choose this and other protected locations where from the meadow plants might survive the region’s worst winters. Like Judd and Raup, Donald Wyman was fas- a low on the northeastern side 2) cold, spot cinated the weather. While as Hor- of Hill site of the by working Bussey (the present ticulturist at the Arboretum from 1935 to Collection of Rosaceous 1970, Bradley Plants) he vigilantly observed and recorded plants’ 3) an open site with good air drainage near responses to various storms, droughts, and un- the summit of Bussey Hill (the present timely freezes. This information formed the site of Chinese Path) core of his many publications on ornamental 5

The Hurricane of 1938

One of the most common notations in the card file of plant records is the phrase "de- stroyed in hurricane." Over the course of the Arboretum’s history, hurricanes have swept through and shaken up the living collections by snapping branches, splintering trunks, and uprooting trees of all sizes. Among the major named hurricanes to hit the Arbore- tum over the last half century (they weren’t given names by the National Weather Service until 1950) were "Carol" and "Edna" in 1954, "Donna" in 1960, and "Gloria" in 1985. None of these storms did half the damage caused by an unnamed storm that blew in from the south at about 4:30 p.m., 211 September 1938. This hurricane followed a week of soaking rains that had permeated the ground and raised rivers and streams to

Devastation on the slope behind the adminis- tration bmldmg. The bmldmg m the background is the Adams Nervme Asylum, and 7udgmg by its toppled chimney, it too suffered from the 87 mph wmds of the hurricane of 1938.

flood stage, creating unstable soil conditions and making large trees vulnerable to gusting winds of up to 87 miles per hour. By 8:00 p.m., when the wind finally died down, the power was out and trees were strewn across the grounds like pick-up sticks. In total, 1490 Arboretum trees were blown down in a Fallen trees blockmg South Street after the matter of four hours, a new hurncane of 1938. It took months to clean up the mspiring phase of the nearly 1500 trees that blew over, and even now, planting and-despite temporary 58 years later, the hurmcane’s effects can still be devastation-ultimately reinvigorating the * seen throughout the collections. collections.

* Information on the hurricane of 1938 comes from three sources: Ida Hay’s book Science m the Pleasure Ground, William Judd’s weather records in the Arnold Arboretum Archives, and the Arboretum’s Bulletm of Popular Information, senes 4, volume 8 ~1940~. 6

plants and aided in the development of the making general comparisons. According to Arnold Arboretum hardiness map, the precursor Lautzenheiser’s reports, the past three summers to the current USDA hardiness map. Wyman have been warmer and drier than usual, but observed the effects of harsh weather on plant this trend has been interrupted by typical New groups such as rhododendrons, conifers, and England inconsistencies and exceptions.5 legumes. His articles gave gardeners a sense of 1995: The Year in Review which plants could survive not only the "nor- mal" weather for the region, but also the occa- Nineteen ninety-five was a remarkable year for sional extremes that must be factored into any a number of reasons: from 1 December 1994 functional description of hardmess. In a 1945 through 28 February 1995, average temperatures article about winter injury suffered by rhodo- were 3 degrees warmer (making the average dendrons, Wyman wrote: mark 33.9 degrees F and mterfering with the dormancy of many plants) and there were If there is factor which can be any one singled 17.2 inches less snow than normal. Nineteen out as being responsible for the m~ury, it might ninety-five had the driest January 1 through well be the rainfall, or better, the rainfall and the 16 on record with 16.87 inches snowfall.... Dunng November and December of September only of 12 inches less than 1943 there was a rainfall of only 3.15 inches- precipitation-roughly less than half the normal amount for those two normal-depriving plants of essential moisture months. By November there was already a 5 inch throughout the entire growing season. October deficit in the rainfall. Hence the rhododendrons was 3.6 degrees warmer and had 3.12 inches went into the winter (after the soil had frozen) more precipitation than usual, inspiring new in a very dry condition. With practically no growth in plants that had gone dormant in snow and of water from the cover, evaporation response to the drought. Late November and soil surface the the situation throughout winter, December a record snowfall ‘~ early brought of 28 was aggravated. inches, doubling the total for the entire winter Wyman used his observations to make recom- of 1994-1995. Added to these deviations from mendations for planting, caring for, and protect- normal weather patterns was the siren storm ing those species he found prone to damage that coated the Arboretum in ice for six days in under unfavorable conditions. Perhaps his best early March. This spectrum of extreme weather advice was to avoid planting broadleaved ever- made extra work for the grounds staff over the greens in southwest-facing locations where they course of 1995, and though it might take a few might suffer both m summer and in wmter. years to determine the extent of the injury sus- On 15 August 1962, the Arnold Arboretum tained by plants in the living collections, it gave became an official substation of the National the institution ample opportunity to further its Weather Service. Every morning at around 8:00 investigations of plant hardiness and drought a.m., a member of the greenhouse staff reads a tolerance. rain gauge and a maximum/minimum ther- mometer to gather data for climatologist R. E. Mild Winter Lautzenheiser. Each January, Lautzenheiser pro- In early December 1994, after four days of mean duces a comprehensive summary of the past temperatures of above 50 degrees F, curator year’s weather, including a historical perspec- Stephen Spongberg toured the collections to see tive, part of which is printed in Arnoldia. how the plants were responding to the unsea- Although Lautzenheiser’s observations are sonable warmth. Walking on the west side of primarily based on data from Boston’s official Bussey Hill, he noticed a specimen of Lonicera weather station at Logan Airport (which tends standishii f. lancifolia in full flower. Although to have more precipitation and to be slightly in warmer climates this species may flower in warmer in the wmter and cooler in the summer winter, at the Arnold Arboretum it has tradi- than the Arboretum), those data are similar tionally flowered in early spring. In fact, in enough to the Arboretum’s to be useful in "Notes From the Arnold Arboretum" in the 23 7

A graph showing normal monthly precipitation (m inches) m Boston and the actual amounts for 1995 at the Arnold Arboretum and Logan Airport The subtle differences m rainfall between the two locations result from a combination of proximity to the ocean (Logan is closer) and elevation (the Arboretum is higher).

May 1888 issue of Garden and Forest, J. G. Jack These mild temperatures and lack of snow mentioned that this taxon was flowering in cover came as a relief to some after the very cold early May.6 Aware of the opportunity to see and wet winter of 1993-1994. Anyone who variation in the flowering time of similar spe- spent that winter in New England remembers cies, Spongberg initiated a winter-long, weekly the relentless snow, high winds, and cold tem- patrol of the grounds to search for other plants peratures that arrived in December 1993 and flowering out of sequence. This search was stayed through March 1994. With 96.3 inches of fruitful: fully fourteen taxa, from Chaenomeles snow recorded at Logan Airport (about 57 inches japonica to Viburnum farreri ’Candidissima’, more than average), that winter surpassed the flowered in December, with many continuing to previous record of 89.2 inches set in 1947-1948.7 flower intermittently throughout the winter In 1965-1966, a season with two feet less snow and into the spring. The winter of 1994-1995 than either of the winters mentioned above, was also remarkable for its lack of snow. There Donald Wyman wrote about the effects of heavy was only one significant storm (6.5 inches on snow on the living collections. In his article, February 4), and the total snowfall for the sea- Wyman discussed the potential damage from son was 14.4 inches-6.7 inches less than Bos- the weight of wet snow on densely branched ton received in just the month of December plants and recommended that gardeners con- 1995 alone. cerned about their plants go out with "a bamboo 8

Plants that flowered in winter

Chaenomeles japonica Prunus subhirtella v. ascendens /Japanese flowering quince) (Weeping cherry) Chaenomeles speciosa ’Nivalis’ Prunus subhirtella v. autumnalis (Nivalis flowering quince) (Autumn-flowering cherry) Euonymus bungeanus v. semipersistans Rosa’Seafoam’ (Seafoam rose)

(Winterberry euonymus) . Spiraea x arguta (Garland spirea) Tasminum nudiflorum (Winter jasmine) Syringa vulgaris ’Princess Marie’ Lonicera standishii f. lancifolia (Princess Marie lilac) (Narrowleaf Standish honeysuckle) Viburnum x bodnantense ’Dawn’ kobus (Kobus Magnolia magnolia) Viburnum farreri ’Candidissima’ Prunus nipponica (Takane cherry) pole, a broom, or rake"8 and tap the snow off difficult to find and repair. Over time rot will set threatened branches. He does caution against in on the jagged breaks, followed by disease, cre- being too rough-one might make matters ating problems that will be visible for twenty worse for the tree-but neglects to warn against years or more. Among the notable wounded standing directly beneath the tree being swept. were Acer diabolicum, AA 2625-A, collected by Charles Sargent in Japan in 1892 and planted The Ice Storm near Willow Path, and two mature specimens of On 28 February 1995, as a light rain fell on Bos- Franklinia alatamaha, AA 2428-3-A and C, ton, the temperature dropped 10 degrees over- growing on Chinese Path. night. The next day the Arboretum was glazed in ice. Typically, ice from a storm like this melts Drought quickly as the sun comes out and the tempera- As mentioned above, 1995 had the driest Janu- ture rises, but in this case cold, overcast days ary through September in 125 years of record prolonged the effect for a full week, ending on keeping. The dearth of snowmelt in the spring March 8, when the temperature rose to 67 and of rainfall throughout the entire growing degrees. This unusual phenomenon was a boon season had an immediate and visible effect on to photographers but destructive to the living the living collections. Plants initially raised in collections. For as long as the ice remained on containers were especially hard hit: container- the trees, they were susceptible to breaking in grown plants are more likely to experience the wind or snapping under their own weight. stress because of their constrained root systems Indeed, the curatorial staff recorded that nearly and differences in drainage between the soil sixty trees had to be removed or pruned heavily, in the containers and in the ground where they and countless more lost leaders, branches, and are planted. Most of the Arboretum’s one- and buds to the shearing weight of the ice. Since the two-year-old plantings dropped their leaves by damage often occurred high in the crowns of August and many subsequently died. By early trees and was not always obvious, it has been September even well-established plantings

The ice storm m early March 1995 was destructive yet beautiful. A thm layer of perfectly clear ice remamed on the trees for six days, causing an off-season peak m msitauon as photographers from all over Boston tried to capture the dazzling effects on film. 9 10

showed signs of stress: the leaves of many trees wilted, some dropped prematurely, and fruit production was reduced in nearly all species. The rain that came in late September and stayed throughout the fall perked up the collections a bit, but it also inspired some plants, dormant in response to the drought, to put on new growth. This tender new growth did not get a chance to harden off and was killed in early November as temperatures dropped below freezing on two successive nights. Viewed alone, the 1995 drought was destructive; combined with a wet fall and the subsequent frost, it could prove to have been devastating. Mature specimens of Styrax obassia are among the Arboretum’s most handsome plants. Unfortunately, this species suffered conspicu- ously from the combination of last year’s dry summer and wet fall. The foliage of AA 1500- 77-A and B dried out in mid-July, roughly one month after flowering, and the desiccated leaves remained on the trees until the second week of September. No new growth occurred during this time and very few fruits developed, a sign the trees had gone dormant. In the early fall, a sig- nificant amount of rain fell and the average tem- perature was about three degrees warmer than normal. These were perfect conditions for new growth, and the trees responded by dropping their dead leaves, putting out new foliage, and flowering. In fact, 1500-77-A was flowering on November 11, five months out of schedule, when a hard frost killed all of its succulent new growth. The drought was doubly damaging to specimens of Styrax obassia. Kept from produc- ing enough photosynthates over the course of the summer, the plants went dormant; forced out of dormancy in the fall they were slammed with a hard frost. It will be interesting to see how these trees will respond this coming spring. This was not the first time Arboretum plants have experienced a combination of drought fol- lowed by deluge. After a wet and stormy 1938, the summer of 1939 was very dry. Only .34 inches of rain fell in July of that year, as opposed to 11.10 inches in 1938.9 The overwmtenng flowerbuds of the prmcess tree July Exasperated by this broad Donald wrote (Paulownia tomentosa), encased m ice, testify to the difference, Wyman attractions of the ice storm; at top, breakage in the about the condition of lilacs, rhododendrons, collections shows its destructive side. and viburnums in the living collections and be- 111

moaned the unpredictability of New England weather. "[I]t would seem," he wrote, "that the plants in eastern Massachusetts are being sub- jected to all the vagaries which an unpredictable Nature can provide in the short period of one year."’° His complaint did not go unanswered: after three months of drought, it rained heavily throughout August 1939, adding yet another loop to the climatic roller coaster Arboretum plants are forced to ride. Plant Response Of course, lack of snowmelt and rainfall relate to the amount of available water, and as any gardener who has neglected to water his plants knows, it is axiomatic that plants need water to survive. In an herbaceous plant, response to drought is obvious and immediate: plant cells- deprived of the water that provides the mternal pressure to keep their cell walls rigid-collapse, and the plant wilts. Trees and shrubs, supported by woody cells used for water storage and trans- port, show a more subtle response, generally suffering only leaf scorch, wilting, or, in the worst cases, defoliation. When the soil is moist, fine feeder roots just below the soil surface take up water through osmosis. This water, powered by evaporation from a plant’s leaves, flows in a steady stream from the roots, through the trunk and branches and to the leaves where it is used A recently planted hickory (Carya sp.) showing the in and to maintain cell photosynthesis pressure. full effects of six months with less than normal During a drought, transpiration occurs at a rate precipitation. By September, the majority of new faster than the uptake of water from the soil, plantmgs were equally desiccated, and many will causing leaves to dry out and interrupting pho- need to be replaced tosynthesis and sugar production. If drought conditions persist, severe water loss will inter- combination of a slimy coating called mucigel rupt normal growth, increase susceptibility to on their exterior surfaces, a waxy coating called insects and disease, and upon the destruction of suberin on their interior surfaces, and a complex enough actively growing cells, cause death. system of membranes that works like a one-way Why are some species better able to with- valve. Drought conditions mspire some plants stand drought than others? Some plants, par- to close the stomata on the undersides of their ticularly those native to arid climates, have leaves during the heat of the day, reducing the developed measures to conserve water. Obvious intake of carbon dioxide and, therefore, the rate examples are succulents and cacti with waxy, of photosynthesis and water consumption. water-conserving surfaces and a large portion of Similarly, broadleaved evergreens curl their each of their cells dedicated to water storage. To leaves during hot, dry weather and severe cold prevent the water and nutrients absorbed from spells to reduce the surface area exposed to sun moist soil from leaching back out when the soil and slow the rate of transpiration. In winter, dries, the root cells of nearly all plants use a when the soil freezes and roots can’t absorb 12

water, deciduous trees in temperate regions are limited to immediate effects like wilting drop their leaves and go dormant just as some leaves, reduced fruit production, and premature dry-seasonal tropical trees drop their leaves to leaf fall. conserve water during the annual dry period. Depending on soil type and exposure, the Cultivated trees and shrubs are more prone to location of plantings within the Arboretum drought damage than those occurring naturally. either limited or compounded the injury caused In an artificial landscape like the Arnold Arbo- this past year by the lack of water. Ironically, retum, human error in matters such as siting the area by Centre Street considered to be the may expose plants to conditions that exceed most favorable for planting cold-tender speci- the capacities of their natural defenses. Hardy, mens turned out to be the location hardest hit moisture-loving plants like willow or alder will by this year’s drought. Nearly all taxa growing suffer during a dry period if placed on a well- there showed some degree of damage, including drained slope but will do well if planted where Clethra alnifolia, Stewartia spp., Magnolia the water table is high. Given this potential macrophylla, Rhododendron calendulaceum for error, Arboretum horticulturists must look (previously thought to be the most drought- carefully at specimens in a variety of sites on tolerant azalea), and Styrax obassia. In contrast, the grounds in order to make useful judgments the native and naturalized plants growing in about a species’ drought tolerance. Since it wooded areas (Carya spp., Quercus alba, Tsuga is impossible to ascertain the longterm physi- canadensis, Betula lenta, Acer spp.) showed less ological effects of drought based on one season severe signs of stress-they are adapted to the of observation, the measures of plant response extremes of this climate. The area near the s 13

Plants that resisted the effects of the drought of 1995

Aesculus turbinata ~ Magnolia fraseri (Fraser magnolia) (Japanese horsechestnut) Magnolia salicifolia Aralia californica (California aralia) (Anise [or willow-leaved] magnolia) Bumelia languinosa Poliothyrsis sinensis (Woolybucket bumelia) Sorbus yuana (Yu’s mountain ash) Chionanthus retusus (Chinese fringe tree) Viburnum rhytidophyllum Enkianthus perulatus (White enkianthus) (Leatherleaved viburnum) ponds, including the Bradley Collection of Rosa- In general, shrubs, handicapped by their shallow ceous Plants and the legume collection, pre- roots, performed worse than trees. The table on sented a puzzle: by late August, as the ponds page 12 lists species that showed signs of stress became puddles, plants growing adjacent to the regardless of where they were planted. water-such as Hamamelis virginiana and While as a whole the living collections looked Nyssa sylvatica-had dropped their leaves listless all summer, some taxa showed little or while those of the same species planted twenty no negative effects of the dry weather. This was feet away on higher, drier ground maintained due to factors such as the plant’s native habitat their vigor throughout the summer. or, in the case of cultivars, improved selection. Drawing conclusions from the condition of A notable example of drought-tolerant plants individual specimens in the living collections was a group of crabapple cultivars (Malus spp.)( is not always straightforward. While most Arbo- retum plants are left to fend for themselves, there are some exceptions to this tough-love approach. To ease the transition from the nurs- ery to the grounds, all new plantings are watered during their first two growing seasons. Given the intensity of last year’s drought, the fall 1994 and spring 1995 plantings would have needed more watering than usual to survive. Limited by the size of the Arboretum and the 500-gallon capacity of our water wagon, the grounds staff could not water them sufficiently to counteract the effects of the drought. Most of these plants suffered conspicuous injury and many will need to be replaced or severely pruned. Conversely, the lilac collection, the Hunnewell Building landscape, and the Bradley collection are served by an irrigation system and were watered throughout the summer; therefore, no valid conclusions could be drawn from the condition Chionanthus retusus (Chmese fringe tree) on Chi- of in those locations. However, the vast plants nese Path. In spite of the drought, 1995 was a good of the collections were not majority watered, year for this plant It flowered profusely in May and and many established plants showed some de- was covered with bnght blue fruits m September, gree of wilting, leaf scorch, or retarded growth. makmg this a good plant for fairly dry sites. 14

generously donated in March 1995 by Schmidt Nursery in Oregon. These plants retained their foliage throughout the summer and actually showed a little growth. As staff waited ner- vously to see how mature pines, spruces, and firs would respond to the lack of rain, they were amazed to see that the majority of the comfer collection held its own-little immediate dam- age could be seen. Other trees and shrubs that demonstrated resilience regardless of where they were planted are listed on the preceding page. This table is meant to supplement tradi- tional lists of drought-tolerant species (Flint 1983, Wyman 1986) and mcludes only trees and shrubs not already widely recommended for planting in dry sites.

If the weather sometimes seems engineered to aggravate horticulturists, it also permits us to learn more about the plants we grow. Bad weather has played an important role in shaping the Arnold Arboretum, both as a scientific insti- tution and a public landscape. In some ways the Arboretum is a sustainable landscape: limited by insufficient irrigation and the size of the col- lections, the grounds staff cannot go to heroic lengths to protect plants from drought and cold, which leaves only those species tough enough to make it on their own. This laissez-faire management, along with a history of detailed weather and plant records, has aided the institu- tion in its research by enabling Arboretum hor- ticulturists to determine of the hardiness of many exotic species. According to the records, the spring and summer of 1995 were the driest in 125 years of record keeping-by far the most extreme year in the recent cycle of drought. The plants in the living collections showed a spec- trum of responses to the lack of water, providing the opportunity to make some generalizations about their hardiness. Since the makeup of the living collections is always changing, these experiments never become redundant and new information is added with every new storm or drought. It is too to know the extent of the The fruits of Sorbus yiiana, Aesculus turbinata, and early per- manent from last Poliothyrsis sinensis. These species held up well damage year’s weather, but during the drought of 1995 and should be considered the cumulative result of the ice storm and for plantmg m sunny, well-dramed sites. drought will probably be the decline of many 15

plants in the Arnold Arboretum’s living collec- 30(5/. 191. Looking at the amount of precipitation recorded at versus the amount for the Arnold tions. In any case, the grounds staff and interns Logan Arboretum, one can see how similar (but not will be and next busy planting pruning year, identical) these amounts are. Using Fordham’s article perpetuating the tradition of testing woody as a guide, one might infer that just as different plants for their ability to endure the inevitable sections of the Arboretum show different average onslaught of "Nature’s vagaries." minimum temperatures, they also might show variation in rainfall. One could investigate microclimates ad nauseum, and in order to avoid this Endnotes I have chosen to use the statistics from Logan. 1 Garden and Forest, edited by Charles Sargent and 7 published from 1888 to 1897, was a botamcal and J. G. Jack, Garden and Forest (1888/ I. 154. horticultural catchall. It included a mix of articles about landscape architecture, timber management, 8 Once again, R E. Lautzenheiser provided these public policy, and garden history as well as figures. descriptions of cultivated and wild plants. 9 D. Wyman, Arnoldia (1966) 2G( 1 2. 2 W. J. Judd, Arnold Arboretum Archives. The Arbo- io retum’s archives are a storehouse of information D. Wyman, Bulletm of Popular Information (Arnold pertaining not only to the history of this institution Arboretum), Series 4, VII (9~. 41. but to the of American history horticulture, botany, ~’ and forestry. I found William Judd’s notebooks next to Ib~d. old accession books, above Charles Sargent’s personal correspondence, and across from E. H. Wilson’s References photographs of his travels through China. Given H. L. 1983. Plants for Eastern North the well-orgamzed, comprehensive nature of the Flint, Landscape Amenca NY: John Wiley & Sons. - archives, it was very easy to construct a history of recording the weather at the Arnold Arboretum. Hay, 1. 1995. Science m the Pleasure Ground Boston: 3 A. J. Fordham, Arnoldia (1970) 30(5). 186-193. Northeastern Umversity Press. Fordham’s article provides a detailed description of the variations in minimum temperatures at each of Mauseth, J. D. 1988. Plant Anatomy. Menlo Park, CA: these locations given a range of different wind Benjamin Cummings. conditions and cloud cover. It also describes the differences in temperatures and amounts of Smclam, W. A. 1987. The Diseases of Trees and Shrubs precipitation between the Arnold Arboretum Ithaca, NY: Cornell Umversity Press. Weather Station and Logan Airport. D. 1986. The NY: ’ Arnoldia Wyman, Encyclopedia of Gardening Donald Wyman. (1944/ 4~ 4/: 19. Macmillan

5 Mr. Lautzenheiser’s work is a weather watcher’s dream. He produces monthly and annual reports with Zimmerman, M. H. 1983. Xylem Structure and the Ascent Berhn: detailed information about cloud cover, degree days, of Sap. Sprmger-Verlag. precipitation, and temperature. See page 36 of this issue for the 1995 summary of weather data.

~ Once again, see Alfred Fordham’s article on Todd Forrest maintains the plant records system for the microclimate at the Arnold Arboretum, Arnoldia Arnold Arboretum. 16 Hardy Asian Alders

Kim E. Tripp

The alder, whose fat shadow nourisheth- Each plant set neere him long flourisheth. -William Browne, 1613, Brittania’s Pastorals, Book I, Song 2

The search for new and unusual plants with About thirty-five species of Alnus are found handsome ornamental character and reliable around the world, all of them in the northern landscape performance is as old as horticulture hemisphere with the single exception of A. itself. The peak period of plant exploration may acuminata, which extends below the equator have passed with the likes of E. H. Wilson in the into Andean South America (Furlow 1979a, b). earlier part of this century, but at the Arnold Among the alders are some of the most cold Arboretum new plants from around the world hardy of broadleaved trees, including shrubby are still being added to the living collections and species in subarctic regions as well as numerous evaluated as ornamentals. species adapted to cool mountain climates. Potential new ornamentals must meet a They are most often found growing on poor demanding set of criteria before being declared soils, especially in wet conditions, and will good landscape plants. They should thrive in thrive where many other woody plants cannot.’ diverse landscapes under conditions of low maintenance, with minimal supplemental The Genus Alnus water and fertilizer. They should be reasonably Alders are of interest biologically, botanically, drought tolerant and suffer no significant pest or and ecologically. The genus comprises an an- disease problems. They must be easy to propa- cient group of deciduous trees and shrubs in the gate using standard nursery techniques and Betulaceae (birch family), of which the closely grow rapidly enough to be commercially profit- related Betula and Alnus may be considered the able. Obviously they must also possess attrac- most primitive members (Furlow 1979a). The tive ornamental features, preferably several for Latin name Alnus is variously believed to derive multiseason interest-showy flowers, fruit, fall from the classical Latin verb alo (to nourish, color, attractive winter habit or bark color, probably referring to its usual close association or handsome foliage with useful shade or ever- with water); or from the Celtic al (near) and green characteristics. lan (riverbank) (Furlow 1979a). Indeed, Alnus The great wonder of the woody plant world is are most often found growmg in moist or wet the number of new plants that are continually habitats-in or near streams, rivers, ponds, being found to meet these criteria-either as lakes, swamps, wetlands, and on moist slopes- brand-new finds from the wild or from breeding but some species inhabit moderately dry upland programs, or as rediscoveries from the forgotten sites, and others can grow in a range of environ- corners of gardens and landscapes. In the latter ments from very wet to relatively dry. They are category, one neglected but fascinating genus most often found at low to middle elevations, holds extraordinary promise for demanding but a few notable exceptions climb nearly to modern landscapes-the genus Alnus, or alder. timberline.

This pair of Manchuman alders (Alnus hmsuta) along Willow Path at the Arnold Arboretum makes a handsome feature m the wmter landscape 188

which bears nodding pistillate cat- kins.) One related group of alders, the subgenus Clethropsis (A. maritima, A. nepalensis, A. mtidaJ, flowers in the fall, while all the others flower in the spring. As seed develops, "female" catkins mature into small dry infructes- cences, oval in shape, with many woody scales enclosing single- seeded, narrowly winged nutlets that are later dispersed by wind and water. These infructescences re- semble those of birches when young, but whereas the infructescences of Alnus are woody and persist after the seed matures, those of birches are papery and fall apart. Alders’ pistil- late catkins can develop into mature infructescences even when seed has not been fertilized; in that case, the seed develops into an empty, shrunken nutlet. There is some evi- dence of limited development of viable seed without fertilization through a process known as apo- mixis (Furlow 1979a, Santamour 1995). Whether filled with viable seed or not, mature alder infructescences look very much like the diminutive true cones of a conifer. On most alders of flowering age (at least two years old), the spent "cones" are con- after the The refmed silhouette of Alnus japonica is lovely in all four spicuously persistent long seed has a delicate seasons of the year. fallen, producing ornamental feature as well as a dis- Like other members of the Betulaceae, alders tinctive field-key character. These attractive are monoecious, bearing separate staminate infructescences are sometimes gold plated and ("male") and pistillate ("female") catkins, or sold as jewelry. aments, on the same tree. (Catkins are compact Perhaps the most fascinating aspect of alder aggregates of individual flowers in a single biology is the ability of all species to "fix" atmo- structure, like the staminate "tassles" of oak.) spheric nitrogen in a process analogous to that Both staminate and pistillate catkins develop of leguminous plants like beans and peas. Fixing in the axils of the leaves or as the terminal bud. nitrogen is the process of converting atmo- Staminate flowers mature on pendent catkms spheric nitrogen into a form usable by plants similar to those of birches, while the small pis- and other biota. This unusual ability enables tillate catkins are for the most part relatively alders to pioneer successfully on sites of low fer- erect and less conspicuous at time of flowering. tility, where over time they contribute signifi- (An exception is Alnus firma var. multinervis, cant nitrogen to the soil, principally as leaf litter 19

(Binkley et al. 1994). As a result, Alnus is often one of the first species to establish itself after fire, clear cutting, volcanic activity, or other disturbances to forest environments (Furlow 1979a~. Its vigorous growth can prevent or sig- nificantly inhibit colonizing by other plants, both wild and cultivated. For example, follow- ing the eruption of Mt. St. Helen’s, vigorous hybrid poplars (PopulusJ were planted on mud- flows caused by the eruption. Alnus rubra (red alder) seedlings rapidly established them- selves naturally on these sites, however, out- growing the Populus and other species to the extent that after six years the stands on the mudflows were 93% Alnus (Binkley et al. 1994). Alders’ nitrogen-fixing ability has also been used to advantage for many years in mine spoil reclamation (Tarrant 1968).(. Their ability to fix nitrogen combined with their rapid growth rate also permits alders to outperform other species in managed environ- ments, sometimes in an undesirable way. For example, in the northwestern United States,

The graceful fohage and catkms of Alnus japonica are lllustrated in this drawmg by C E Faxon. From the Archives of the Arnold Arboretum

native Alnus rubra was historically eradicated from recently harvested and disturbed sites by commercial forestry managers who considered it a weed in competition with high-value coni- fers. More recently, red alder’s rapid growth and its ability to produce biomass on marginal sites is receiving the recognition it deserves, and its use-both as a "nurse crop" to provide nitrogen for higher value crops and as a primary crop whose wood value is itself on the increase-is now a major subject of research in United States forestry science (Hibbs et al. 1994). Hardy Asian Alders of Ornamental Potential From a horticultural standpoint, the alders’ ability to fix nitrogen and to thrive in wet soils makes them a natural choice for many difficult sites with low fertility. The horticultural merit of ornamental alder has been far more The bold foliage and catkms of Alnus hirsuta are species drawn m fme detail by C. E. Faxon. From the widely appreciated in Europe, Asia, and western Archives of the Arnold Arboretum. North America than in the eastern United 20

States, possibly because the alders native to hardmess. Rather than attempt to treat all of the those areas include handsome, full-sized trees. approximately thirty-five alder species in an In contrast, the alders native to eastern North article of this scope, I have chosen to discuss America are generally a shrubby, disheveled only hardy Asian alders of particular horticul- lot-biologically tough and ecologically impor- tural merit-plants which, unlike their Euro- tant, but less than aesthetically pleasing. This pean cousins, have been neglected as specimen, has given the entire genus an undeservedly poor shade, and street trees. Herein, "Asian" refers to reputation in the eastern half of the United the regions inclusive of China, Japan, Korea, States, where the vigor and attractiveness of Sakhalin, the Kuriles, Kamchatka, and the Alnus could make an important contribution to eastern and central regions of the former USSR gardens and other landscapes. (that is, Russia’s non-European regions); while European species like Alnus glutinosa and A. "hardy" refers to plants that will survive and cordata are already widely grown in Europe and grow in areas with winters at least as severe as the United States and each has notable culti- those of USDA hardiness zone 6. vars. The Asian alders, on the other hand, have Many alders fall into that nebulous category received little attention, although they include of "large shrubs or small trees," depending on some of the most beautiful taxa of the genus- where they are growing and on whether they taxa with rapid growth rates, no significant pest have been pruned to one or a few main trunks. or disease problems, and useful degrees of cold Many species that grow at both low and high

The Other Asian Alders*

Two categories of Asian alders are not in- are often nearly round with a notched apex cluded in this article: the ornamental but and can be 4 to 5 inches in diameter, the not hardy, and the hardy but not ornamental. size of teacup saucers. Leaf size and shape Some species, like the beautiful Alnus are fairly variable. Its close relative, A. subcordata of the Caucausus, which is matsumurae, is a medium-sized tree (occa- widely grown in Europe, and the recently sionally shrubby in the high mountains) that named white-barked A. glutinosa ssp. is similar to A. fauriei, which has an overlap- betuloides, fall into the former group (Ansin ping range in Japan but which grows up into and Ozder 1993). Also in that category are higher elevations (Ohwi 1965, Sargent 1916). the tender but lovely A. formosana and A. fruticosa is the common, widely dis- A. orientalis and the unique but only persed, shrubby alder of northeast China, semihardy A. cremastogyne of China that Mongolia, European Russia, and much of the bears its "cones" on long pendent peduncles. former USSR (including Siberia). It is a plant In the second group are hardy Asian alders of great tenacity that thrives in an incredible that are of botanical, if not horticultural, range of soils and conditions, from wet interest. Alnus trabeculosa is a small to lowlands to alpine scree (Hulten and Fries medium tree of southeastern China and, 1986). Some botanists assign A. fruticosa rarely, Japan (Ohwi 1965). Its foliage is oval to the genus Duschekia (noted under and narrows abruptly to a distinctively long, A. maximowiczii, Shemberg 1992), while pointed apex. A. fauriei grows as a large others elevate the populations found on the shrub or small tree in northern and central Kamchatka peninsula to a different Alnus Japan (Ohwi 1965). The foliage of this spe- species, A. kamtschatica (Czerepanov 1995, cies is its most distinctive feature. Leaves Voroshilov 1966, 1982). * See Krussman ~ 1984) and The Royal Horticultural Society Dictionary of Gardemng 1992) for overviews of the entire genus. 21

elevations usually grow as trees but are shrubby at the highest elevations in their range (for ex- ample, Alnus hirsuta, A. matsumurae/. Most of the species described below develop as trees of various heights and dimensions; an exception is the shrubby A. maximowiczii, which is included for its horticultural potential. I have included the USDA hardiness zones in which the plants are likely to survive. With few exceptions, the germplasm of these species now grown in the United States originated from propagules of relatively limited geographic prov- enance. No doubt cold hardiness for most of these species could be improved by future col- lections from their coldest provenances. The ornamental attributes of Asian alders are quiet and subtle but nonetheless effective in the landscape. None have dramatically showy flow- ers, but some have eyecatching and colorful cat- kins in spring. None have fall color, but all have persistent catkins that are delicately attractive. The arboreal alders also have very handsome winter architecture of diverse types, and some have beautiful, beech-like bark.

Alnus firma, native to Japan, is a deciduous, multi-trunked tree of small to medium size, or occasionally a large shrub, that can reach 40 feet in the wild but is generally seen in cultivation at heights of 15 to 25 feet, depending on habit. It has a narrow, graceful spread with somewhat The silvery gray bark of Alnus hirsuta is ornamental pendent branches, and its foliage is among the m wmter. loveliest of any deciduous tree. Its glossy, emer- ald green leaves, about 2 inches wide and 4 leaves and twigs. The degree of pubescence var- inches long, are regularly, slenderly oval and ies somewhat but where it is heavy, it is quite deeply veined. When emerging, the foliage showy. A. firma var. multinervis (sometimes appears pleated and is as attractive as when named A. pendula) is native to Japan, Korea, and fully expanded. Hardmess of this species varies eastern Asia. It differs from other A. firma taxa widely by provenance and is reliable through in bearing more numerous pairs of veins on the USDA zone 7, but its subspecies are generally leaves, a trait that adds to its ornamental char- hardy through zone 6. In the wild, A. firma is acter. Its pistillate catkins are nodding or pen- usually found in wet sites near water and does dent, in contrast to the more erect catkins of best with full sun or light shade in moist to other species-a characteristic that has been the wet soils that do not dry out significantly. In basis for elevating this taxon to the species level containers, however, it tolerates moderately (A. pendula) by some authors (Ohwi 1965).(. uneven watering with no adverse effects in As a small ornamental tree, Alnus firma var. the Northeast. multinervis offers graceful habit, exceptionally Alnus firma var. hirtella is also native to handsome foliage throughout the growing sea- Japan and resembles the typical variety except son, persistent infructescences of delicate orna- for a dense orange to light tan pubescence on the mental character, and unstoppable tenacity in 22

sites of low fertility. Growth is rapid in contain- ers and in the field. A. firma var. multmervis might make an exquisite small tree for large containers in pocket parks or urban squares, or a lovely lawn tree for small, low-fertility subur- ban lots where the topsoil has been stripped.

Alnus hirsuta (Manchurian alder) is a large de- ciduous tree reaching 50 to 80 feet in the wild and, with age, similar heights in cultivation. It has an upright, uniform, pyramidal habit simi- lar to that of mature A. glutinosa. Its leaves are rounded to broadly ovate, about 3 inches wide and 3 to 4 inches long, variably toothed and pu- bescent. The foliage retains a good, grass-green color throughout the season, while the spent infructescences are prolific and persist attrac- tively through the winter. Bark color is quite variable, ranging from a warm, light silvery gray to brown-charcoal, and it can be as ornamental as that of European and American beeches (Fagus sylvatica and F. grandlfolia). A. hirsuta is hardy through at least USDA zone 4, but the provenance of wide-ranging species like this one can significantly affect cold hardiness; more collecting and testing is needed to determine whether plants from its northernmost prov- enance are significantly more cold hardy than Zone 4. This species and its botanical varieties are widely distributed throughout Russia (including Siberia, the Amur region, Sakhalin, Kamchatka, and the Kuriles), and in Manchuria, Japan, and parts of Korea (Kabanov 1937). In the wild, Manchurian alder is found in a diverse range of conditions from poorly drained river bottoms to dry upland. There are two botanical varieties (rarely elevated to species) distin- guished chiefly by provenance, foliar morphol- ogy, and degree of pubescence. Alnus glutinosa var. mandschurica, found m Manchuria, has rounded foliage and is pubescent only along the veins on the undersides of leaves, while var. sibirica is the essentially glabrous-foliaged form of wide distribution. In cultivation, Manchurian alder is one of the most beautiful and useful of the arboreal alders, thriving in wetlands, moderately dry sites, and sites with moisture. The fohage of the Asian alders -from top to bottom, variable Growth is rapid in Alnus firma var. multinervis, A. hirsuta, and A. the field and in containers (as much as 5 to 6 feet

~aponrca-is diverse and beautiful _ per year). Alnus hirsuta has been grown for 23

about twenty years at the Arnold Arboretum A. ~aponica but has wider leaves and a more and has proven to be one of the most handsome robust habit. and reliable of all the Asian alders here, with no The Japanese alder has a notably narrow and significant pest or disease problems. In addition, elegant silhouette both in summer, with its it is the only one of several Asian species dense, glossy foliage cover, and in winter, when planted at the Harvard Forest in Petersham, its persistent "cones" and appealing habit add a Massachusetts, in the early 1980s that has re- Japanesque character to the landscape. It could mained vigorous in a plantation situation with be especially useful as a low-maintenance shade low maintenance. The handsome bark and foliage of the Man- churian alder, its persistent "cones," uniform Propagating the Asian Alders branching pattern, and stately habit make it an excellent shade tree for parks or streets. Its tol- Alders propagate readily from seed, giving erance of low fertility and of poor dramage or best results when the seed is fresh and has fluctuating moisture enables it to tolerate low- not been allowed to dry out before sowmg. maintenance and urban sites that defeat other If the seed has dried, good results can also shade trees. The vigor and beauty of this species be obtained with relatively short periods suggest that its best individuals should be of stratification (one to two months in a selected and named and that it would be profit- moist medium at 35 to 40 degrees F). It is able to collect more plants from its coldest useful to note that alder species that provenances in the wild. flower simultaneously may hybridize readily where they are found growing in Alnus japonica, Japanese alder, is a deciduous relative proximity (Furlow 1990). Such tree of small to medium size, generally reaching species m the wild are generally kept sepa- 30 to 50 feet, with a narrowly oval habit and rated by geography and habitat, but garden slightly pendent, fine-textured branching. Its plants are freed of these natural limita- elegant leaves of a smooth, glossy, bright green tions. Seed collected from cultivated are narrowly oval, about 1.5 to 2 inches wide alders, therefore, may well give random and 3 to 4 mches long-very finely toothed but hybrid progeny-especially as all the without the prominent venation of A. firma. Betulaceae, including Alnus, are wind- The foliage remains green and glossy very late pollinated and the pollen can travel great into the fall. Its bark is a medium gray, and the distances. spent infructescences are prolific and persist This tendency to hybridize in nature through the winter with delicate ornamental and cultivation has resulted in some con- character. When the staminate catkins flower fusing nomenclature, as well as some at- m spring, many plants develop a distinctive and tractive plants. There are some naturally attractive cherry-red hue. Japanese alder can be occurring, distinctive, consistently named found growing widely in Japan as well as in hybrids (for instance, A. x mayrii/, as well Manchuria, in parts of Russia (near the shore in as many names for putative hybrids that the maritime region, on Sakhalin, and in the have entered the taxonomic literature. Kuriles), and in Korea. It is reliably hardy Alders can also be rooted successfully through at least USDA zone 6; plants from the from softwood cuttings. Cuttings should coldest provenances may be more hardy. Two be harvested when the wood has just be- botanical varieties are distinguished by prov- gun to harden and rooted under relatively enance (A. var. koreana, found in Korea) and frequent mist with pretreatment of moder- by foliar morphology (A. var. minor, with ate concentrations of IBA hormone prepa- leaves much smaller than the species, about rations. Best results have been obtained 2 to 4 inches long). A. x mayrii, an especially when temperatures in the propagation area handsome tree, is a naturally occurring hybrid stayed below 80 to 85 degrees F. of A. japonica and A. hirsuta that resembles 24

tree in narrow strips of poorly drained land, or in on sites with low fertility and drastically fluctu- small courtyards or gardens with poor soil ating moisture conditions. where an elegant deciduous tree is wanted. Alders at the Arnold Arboretum Alnus maximowiczii is a deciduous shrub or For a century, alders have made an important occasionally a small tree that can reach surpris- contribution to the living collections at the ing proportions with great age. (Richard Weaver, Arnold Arboretum. E. H. Wilson was particu- Jr., 1978, reported seeing trunks 3 feet in diam- larly interested in the genus and collected eter from Hokkaido forests.) In the wild it gen- several Asian alders-Alnus fauriei, A. firma, erally reaches heights of 15 to 25 feet, with A. fruticosa, A. hirsuta, A. japonica, and similar spread, but in cultivation in North A. maximowiczii among them-as well as America it is more often seen at heights of 8 to more tender species like A. formosana and 15 feet, with wider spread. Leaves are about 3 A. nepalensis. Charles Sargent was also enam- inches wide and 4 inches long, heart-shaped to ored of the genus and he too collected and wrote broadly ovate, with distinct serrations. They about alders. More recently, Richard Weaver, Jr., emerge a glossy emerald green with handsomely and Stephen Spongberg made significant Alnus prominent venation and darken to a rich, matte collections in Japan and Korea. blue-green as they mature. A. maximowiczii Although championing Asian alders initially begins flowering before the leaves emerge, and felt like an original effort, this is certainly not both staminate and pistillate catkins are sur- the first time their cause has been promoted at prisingly showy. The pistillate catkins are small the Arboretum. Long ago Charles Sargent him- and erect, turning a deep cherry red at flowering self recognized the horticultural potential of time, while the staminate catkins elongate to 3 the hardy Asian alders-offering his premier to 4 inches and turn a golden yellow. While its endorsement for this premier group of woody floral display will certainly not rival the brazen plants. It is especially appropriate, then, to close showiness of trees like the deciduous magno- with words from his Garden and Forest article lias, it does offer an equally lovely, albeit on Alnus hirsuta (then A. tinctoria) and to reit- quieter, spring character. A. maximowiczii is erate that "the object of this note ... is to call widely distributed in Japan (primarily in moun- attention to a promising ornamental tree" tainous areas), in the former USSR (including (Sargent 1897). Sakhalin, Kamchatka, and the Kuriles), and in parts of Korea. It grows in a wide range of eleva- Literature Cited to but also de- tions, climbing alpine heights Ansm, R., and Z. Ozder. 1993. A new taxon of black scending to sea level in some areas. This species alder-Alnus glutinosa subsp. betuloides has been included by Russian botanists in their (Betulaceae). Kara~a Arboretum Magazme, cilt II: 47-51. split genus Duschekia (Czerepanov 1995), which has also included several other of species Binkley, D., K. Cromack, Jr., and D W. Baker. 1994. alder from time to time. The genus Duschekia Nitrogen fixation by red alder: biology, rates is not widely accepted by Western botanists. and controls. The Biology and Management of Alnus maximowiczii is a handsome shrub Red Alder Ed. D. Hibbs, D. DeBell, and R. Tarrant. Corvallis: Oregon State Umversity that will thrive in virtually any site with full Press, pp. 57-72. sun. It is hardy through at least USDA zone 4 and grows rapidly for a large landscape shrub. Browne, W. 1613. Brittama’s Pastorals, Book I, Song 2. With its appealing spring display and foliage The Biology and Management of Red Alder. that remains in good condition throughout the Ed. D. Hibbs, D. DeBell, and R. Tarrant. Corvallis: Oregon State University Press, p. ix. season, it is a good choice for embankments and other difficult sites where a tall, lush green, Czerepanov, S. K. 1995. Vascular Plants of Russia massing shrub is desired. It is especially useful and Ad~acent States (The Former USSR). : 25

Cambridge, GB: Cambmdge Umversity Press, Sargent, C S. 1897. New or little known plants. Alnus pp.114-115. tinctona. Garden and Forest 10(510): 472.

Furlow, John. 1990. The genera of Betulaceae m the --, ed. (1916) 1988. Plantae Wilsomanae. Vol. II. southeastern Umted States. Journal of the Portland, OR: Disocorides Press, pp. 488-508. Arnold Arboretum 71(1): 1-67. Shemberg, M. A. 1992. Betulaceae. Tomus 5. Flora of I. M. . 1979a. The systematics of the American species Siberia in 14 Tomis. Ed. Krasnoborov of Alnus (Betulaceae/, Part I. Rhodora 81(825/: and L. I. Malyschev. Novosibirsk: Nauka 1-121. Publishers, p. 61.

on . 1979b. The systematics of the Amemcan species Tarrant, R. F. 1968. Some effects of alder the forest of Alnus (Betulaceae/, Part II. Rhodora 81(82G/: environment. Biology of Alder Proceedings 151-248. of Symposium of Northwest Scientific Association Held at Pullman, WA, 1967. Ed. M. Hibbs, D., D. DeBell, and R. Tarrant, eds. 1994. The Trappe, et al., p. 193. Biology and Management of Red Alder. Corvallis: Oregon State Umversity Press. Voroshilov, V. N. 1966. Flora of the Soviet Far East Moscow Nauka Publishers, pp. 3-10, 151-152. Hulten, E., and M. Fries. 1986. Atlas of North European Vascular Plants. I. Konigstein, FDR: Koeltz . 1982. Keys to the Plants of the Somet Far East. Scientific, pp. 312-313, 1030. Moscow’ Nauka Publishers, p. 199. Kabanov, N. E. 1937. Matemals for the Flora of Soviet Weaver, Jr., R. 1978. Japanese journal. Arnoldia 38/3/: Sakhahn. Moscow, pp. 832-833. 83-101.

Krussman, G. (1976/ 1984. Manual of Cultivated Broad- Acknowledgments Leaved Trees and Shrubs. Volume I. Portland, OR: Timber Press, pp. 132-140. The author gratefully acknowledges Irma Kadis for her patient translations from the Russian literature, as well Ohm, J. 1965. Flora of Japan Washington, DC: as Sheila Connor, Peter Del Tredici, Mark Krautman, Smithsoman Institution, pp. 374-376. and Stephen Spongberg for critical discussion and recommendations, or assistance with archival literature. Royal Horticultural Society. 1992. The New The author also gratefully acknowledges the support of Royal Horticultural Society Dictionary the Willowwood Foundation for aspects of the work of Gardening Volume I. NY: Stockton Press, included here. pp. 117-119

Santamour, Jr., F. S. 1995. Flowering, fertility, and fruit Kim E. Tmpp is a Putnam Fellow at the Arnold production m an intersubgenenc Alnus hybrid. Arboretum, using the living collections for research, HortScience 30(7): 1467. teaching, and wntmg. A Nitrogen Fixation: The Story of the Frankia Symbiosis

Peter Del Tredici

Some of the plants we scorn as weeds perform important biological functions. By adding nitrogen to impoverished soils, nonleguminous nitrogen-fixing trees and shrubs play a key role in the process of forest succession.

It’s a great irony of the botanical world that plant growth is often limited by the availability of nitrogen in the soil when almost eighty percent of the atmosphere is composed of dinitrogen gas /NZ~. The explanation lies in the chemical stability of nitrogen gas. Before atmo- spheric nitrogen can be used by plants, it must be "fixed," that is, split and combined with other chemical elements. This process requires a large input of energy and can occur either bio- logically, within the cells of various bacteria, or chemically, in fertilizer factories or during lightning storms. Among all living organisms, only bacteria have evolved the complex biochemical mecha- nisms required for nitrogen fixation. All "higher" plants and animals that are said to fix nitrogen are really only the symbiotic partners of the bacteria that do the actual work. Among plants, the cultivated legumes (peas, beans, peanuts, etc.) are the best-known nitrogen- fixers, but many plant families besides the Leguminosae can also fix On a world- nitrogen. This flat of southern bayberry seedhngs (Mynca wide these as are some- scale, nonlegumes, they cenfera) was supposedly grown both without what negatively called, fix as much nitrogen mtrogen and without the Frankia bactena. One as legumes, but for a variety of historical of the seedhngs, however, did manage to form reasons they have been relatively neglected Frankla-induced root nodules, producmg a clearcut by scientists. advantage over its sibhngs. Quite a few of these nitrogen-fixing non- legumes are native to North America and in the South) on the seashore and on exposed are mostly found in impoverished, sandy soils sandy soils back from the coast; sweet fern low in nitrogen. The most common are (Comptonia peregrina) on exposed, dry, sandy alder (Alnus sp.) in wet, open land; bayberry soils; sweet gale (Myrica gale) in swamps; (Myrica pensylvanica in the North, M. cerifera and New Jersey tea (Ceanothus americanus) 27

in open, wooded sites. On the west coast of North America, various Ceanothus and Alnus species are the most common nonlegume nitrogen-fixers. In the arid mountains of the West, buffalo berry (Shepherdia canadensis), bitterbrush (Purshia tridentata), and the mountam mahogames ( Cercocarpus spp. ~ are important. In southern Flomda, the introduced and somewhat weedy Australian pine (Casuanna spp.) is important for stabilizing beaches, and throughout the Mid- west and East Coast the autumn and Russian olives (Elaeagnus umbellata and E. angustifolia) have been widely planted along embankments. All of highway A Frankra-mduced nodule on a root of sweet fern, Comptonia these plants thrive in poor soils peregnna. Note the upwardly growmg roots emanatmg from the where little else grows. Their abil- lobes of the nodule. ity to fix nitrogen is a significant factor in their survival under conditions that the bacteria, by producing large quantities of the would be inhospitable to ordmary plants. hormones that normally occur in very small In legumes and nonlegumes alike, the actual concentrations in the plant, force the root cells fixation of nitrogen is done by bacteria living to proliferate much faster than normal, causing inside the roots of the host plant. It is a classic multi-lobed swellings, or nodules, to form example of a mutually beneficial symbiosis: the wherever the bacteria have penetrated. Among plant provides the bacteria with sugars and a the actinomycete-nodulated plants, properly re- variety of minerals, and the bacteria provide the ferred to as actinorhizal plants, these nodules host with a usable supply of nitrogen. In the have a well-defined structure and a rather strik- case of the legumes, the bacterium may be one ing appearance, being densely branched and of several different species of the genus Rhizo- more or less spherical. The nodules are peren- bium, a rod-shaped bacterium found naturally nial and increase in size each year, eventually in most soils and available commercially in becoming over an inch in diameter. In some most seed catalogs as legume inoculant. In the plants, such as alder, the individual lobes that nonlegumes, the bacterium involved is an acti- make up the nodule are very tight and compact. nomycete, or filamentous bacterium, in the In others, such as sweet fern, each lobe of the genus Frankia. Unlike the rhizobia, which exist nodule grows out into an upwardly growmg root as discrete cells, the actinomycetes grow in long creating a sort of witch’s broom effect. chains of cells similar to fungal hyphae, but These nodules are the site of nitrogen fixa- much smaller. All of the plants infected by tion. Both Rhizobium and Frankia bacteria pos- Frankia, with one exception, are trees and sess special enzymes, nitrogenases, that allow shrubs, whereas among the legumes both them to transform the nitrogen gas in the air annual herbs and trees may be infected by into ammonium which, in turn, is converted rhizobia. into amino acids. Because the reaction can only The microorganisms enter the plant through occur in a low oxygen environment, the process the root hairs and grow in the cells of the roots, is often dependent on hemoglobin compounds stimulating them to grow and divide. Basically, found in the nodules, which are virtually iden- 28

Several old nodules of the root system of the southern bayberry, Myrica cerifera, growing on the sand dunes along the outer banks of North Carolma. The root, with its attached nodules, was exposed by the wmd, which m this area never seems to stop blowmg. tical to those found in the red blood cells of ani- of nearly seventy years of unsuccessful attempts mals. By binding with oxygen, the hemoglobin to isolate the orgamsm responsible for nitrogen in the nodule helps to create the microenviron- fixation from an actinomycete-nodulated plant. ment that the nitrogenase enzyme requires. It In contrast, the faster-growing Rhizobium is interesting to note that when actinorhizal bacterium was first isolated in pure culture plants are grown in water culture, the young, ninety years earlier, in 1888. This disparity is succulent nodules are often pink in color, due to the main reason why the actinorhizal symbiosis the presence of hemoglobin. is not nearly as well understood as the Rhizo- Work on actinorhizal plants took a giant step bium association. forward in 1978 when a research team that in- In general, actinorhizal plants are sunloving cluded Dale Callaham, currently of the Univer- pioneers in early successional stages of revegeta- sity of Massachusetts at Amherst, the late tion of the north and south temperate regions Professor J. G. Torrey of the Harvard Forest (with the exception of Casuarina and Myrica in Petersham, Massachusetts, and the present species in the tropics). They do best on sandy or author, successfully isolated and grew, inde- swampy soils where nitrogen is scarce and their pendent of its host plant, the slow-growing ability to extract it from the air is a distinct ad- Frankia bacteria responsible for fixing nitrogen vantage. Usually they are not found in shady, in sweet fern (Comptonia peregrina). This was forested situations or on rich farmland, where the first time that the bacteria from any they would lose their competitive advantage. actinorhizal plant of the nonlegumes had been Most nitrogen-fixing legumes, on the other cultivated independently, and it marked the end hand, are tropical and subtropical herbs that 29

have migrated north and become important in agricultural environments. It is primarily because the legumes are involved with food production that they have attracted the lion’s share of scientific attention, but this situation is changing rapidly. People are becoming aware that the potential value of actinorhizal plants is of equal importance, if not equal conspicuousness, to the legumes. Experi- ments have been conducted by forestry manag- ers in which actinorhizal plants are grown in conjunction with various economically desir- able trees: red alder and Ceanothus with Dou- glas fir on the West Coast, alder with poplar for pulp on the East Coast, and Elaeagnus with black walnut in the Midwest. In all cases, the experiments resulted in richer soil and faster growth rates in the desired tree species. In the Northeast, sweet fern, bayberry, and Elaeagnus are used extensively for stabilizing roadside bankings and revegetating traumatically dis- turbed ground. Actinorhizal plants have a much longer his- tory of human use in Europe and Asia than they do in North America. In Japan, the Asian species of Myrica and Alnus are grown in association with various conifers to improve the soil and The root system of Comptonia peregnna four weeks stop erosion, while along the northern coast of after mnoculation with a pure culture of Frankia and the British the sea Europe Isles, buckthorn, bactena. The bactema stimulated the development is cultivated for the Hippophae rhamnoides, of over fifty-five nodules on this ten-week-old purpose of stabilizing shorelines, as well as for seedling. its edible fruit. Throughout the tropics, the genus Casuarina is not only important in stop- Bayberry is an attractive midsize shrub that ping seashore erosion, but is also an important keeps its leaves longer than most plants and is source of fuel and timber in areas that otherwise covered for most of the winter with waxy gray produce very little. The future looks bright berries (the source of bayberry candles). In for the actinorhizal plants, especially in the addition, bayberry is highly salt tolerant and context of forestry and habitat restoration, as performs equally well near the seashore or on land managers move from experimentation highway embankments where road salt applied into implementation. during the winter tends to accumulate. The The fact that actinorhizal plants grow where arborescent alders have traditionally been little else can makes them particularly useful thought of only in terms of land reclamation, for covering bare ground. Apart from this func- but recently commercial nurseries have begun tional recommendation, however, many of to recognize their ornamental potential. Finally, these plants are aesthetically pleasing as well. the autumn and Russian olives, which were Various Ceanothus species, which are widely widely planted in the 1970s, have a beautiful grown in mild climates, are covered in spring- silver-gray foliage and fruits that birds love time with blue, pink, or white flowers. Sweet to feed on. Unfortunately, the birds love the fern, which is fast growing and small, is perfect fruits so much they have dispersed the plant for any situation with full sun and sandy soil. well beyond its initial area of cultivation. As 30

The Australian pme, Casuanna equisetifolia, growmg on the beach at Haena Point on the north coast of Kaual, Hawam. Incessant wave action has exposed the massme, layered root system of the tree. No doubt this species’ability to fix atmospheric mtrogen is pmmamly responsible for its ability to surmve the harsh conditions. 31

a result of this weedy tendency, the olives are no longer recom- mended for large-scale erosion- control plantings. Measurements of nitrogen fixation in actinorhizal plants taken over ex- tended periods of time have shown that pure stands of alder bush are capable of fixing up to 280 pounds of nitrogen per acre per year. This is much greater than the amount of ni- trogen fixed by soybeans (90 pounds per acre per year) or peas (66 pounds per acre per year), but comparable to that fixed by alfalfa. Most of the nitrogen fixed by the actinorhizal plants enters the nutrient cycle through the decomposition of fallen leaves, twigs, branches, and fine roots. This process is much slower than that which occurs in agricul- tural situations, where leguminous cover crops are plowed into the soil at the end of a single growing season. It is worth keeping in mind that the greatest degree of nitrogen fixa- tion, in legumes and actinorhizal plants alike, occurs when soil levels of nitrogen are relatively low. High levels of nitrogen, applied as fertil- izer, tend to reduce bacterial activity. What this means is that the plant and the bacteria work best together The the Russian olme, when conditions are worst: the silvery gray fohage of Elaeagnus angus- tifolia, can be very stmkmg m the landscape, as shown here at the symbiosis is most effective when it Montreal Botanical Garden. becomes most necessary. To put it another way, the nitrogen-fixation symbiosis is Torrey, J. G., and J. D. Tjepkema, eds. 1979. Symbiotic fixation in a dynamic interaction between two indepen- nitrogen actmomycete-nodulated plants. Botamcal Gazette Special Supplement dent that is entered into when eco- organisms 140.SI-SI26. logical conditions are such that neither partner could survive long without it. Acknowledgments The author thanks Dr. of the De- References John Tjepkema partment of Plant Biology and Pathology, University Callaham, D., P. Del Tredici, and J. G Torrey. 1978. of Mame at Orono, for reviewing this article, and Isolation and cultivation in vitro of the acknowledges the late Dr. John Torrey for his actinomycete causing root nodulation in mspiration. Comptonia Science 199: 899-902. Schwmtzer, C R , and J. D. Tjepkema. 1990. The Biology of Frankia and Actmorhizal Plants. San Diego Peter Del Tredici is Director of Living Collections at the Academic Press. Arnold Arboretum. The Year in Trees and Words: Book Note and Excerpt

The Year in Trees: Superb Woody Plants for Four-Season Gardens. Kim E. Tripp and J. C. Raulston. Timber Press, 1995. 204 pages with 206 color plates. Hardcover. $44.95

J. C. Raulston, director of the North Carolina State University Arboretum and a man of many adages, holds that in any given region of the United States, 40 trees and shrubs make up more than 90% of the landscape plantings. If, as he also asserts, somewhere in this country as many as 15,000 different landscape plants are available for the finding, then why do we see the same few over and over? Twenty years ago Raulston started the Arboretum at NCSU to ameliorate this situation by testing the garden-worthiness of a wide range of plants. A recent count of plants collected and evalu- ated numbered 9,000; having identified some of the most viable and attractive, the next task was to encourage their production and use. To that end, during Kim Tripp’s postdoctoral stint at the NCSU Arboretum, one of her weekly chores was a press release in the form of a plant portrait. Those portraits-150 in total-have been joined to 206 handsome color photos, mostly by Raulston, in The Year in Trees: Superb Woody Plants for Four-Season Gardens. Those who’ve heard either Raulston or Tripp speak know that they possess a wealth of information, especially on plant adaptation and response to climate. * This is a book for the plant lover, a celebration of trees and shrubs that’s solid and informative enough for a place on the reference shelf. Although the NCSU Arboretum primarily tests plants for hardiness in the warm, moist summers of USDA zone 7, many of them grow well in New England. A sampling of Tripp’s portraiture follows. Corylus avellana ’Contorta’: Harry Lauder’s walking stick There just is no escaping it-eventually, at some level or another, all gardeners succumb to the quest for the rare and unusual. This yen may manifest as the drive to find and rescue the rarest of native populations of a tiny fern with only five remaining plants that grow in only one spot on the entire planet (currently endan- gered, of course, by planned construction of a transglobal shopping mall) or it may as an . develop insatiable hunger for a cutting of that dwarf, contorted, pink-and- gold-variegated, cutleaved, sterile, chartreuse-flowered form of a hitherto-believed- to-be-extinct, cold hardy to zone 1, heat-tolerant, broadleaved evergreen shrub rumored to now exist only in the collections of the extremely remote Atlantis Botanic Garden (a garden known only to a few seriously intrepid collectors, which refuses to participate in Index Semina exchanges). Whatever form this yearning for the unusual takes, even the most blase of horti- culturists eventually find themselves searching for choice plants of one form or another. One magnificent plant that has long been a traditional source of choice garden character is Corylus avellana ’Cortorta’, Harry Lauder’s walking stick. This unusual shrub or small tree is a contorted form of the commercial European filbert, Corylus avellana, which is grown and highly valued for its delicious nuts. The

’ See "Exploring the Complexities of Plant Hardmess" by J. C. Raulston and Kim E. Tripp in the Fall 1994 Arnoldia (54:3). 33

branching of this form is twisted into striking, spiral contortions throughout the entire plant. It is a spectacular addition to the winter garden, where the sculptural patterns created by the branches can be clearly seen. Native to Europe and parts of Asia and northern Africa, the species Corylus avellana is a small tree or large, woody, multistemmed, thicket-forming shrub. Its deciduous dark green foliage, about 3-4 inches (7.6-10.1 cm~ long and almost as wide, is rather coarse and hairy. The flowers are tiny, with the male flowers borne on long, narrow catkins, and female flowers in shorter, thicker catkins, similar to those of its close relatives the birches (Betula spp.) and alders (Alnus spp.). The catkins of male flowers are yellow and put on a handsome show in late winter before the leaves emerge. The female flowers are much more subtle and require closer inspection to see the delicate but amazingly carmine-colored floral parts emerging from the buds. Corylus avellana ’Contorta’ is much like its parent species with one important exception-its contorted growth. This fascinating plant is interesting in summer because the leaves are also somewhat contorted, but it is at its peak in late winter and early spring. It does not bear fruit. The plant will reach 10 feet (3.1 m~ with some age, but it is a relatively slow grower, which makes it an excellent specimen plant for small gardens. It is completely hardy to zone 4. Corylus avellana ’Contorta’ will perform well in a range of soils in full sun or with a little shade. It is propagated by grafting scion wood of the cultivar onto root- stock of the species. The species understock tends to sucker and the suckers must be continually removed to avoid overgrowth of the cultivar. A Celebration of Crabapples: Book Review

Richard Schulhof

Flowering Crabapples: The Genus Malus. Fr. solid discussion of tree form, and 245 color pho- John L. Fiala. Timber Press, 1995. 340 pages. tographs, crabapples at last have a work that Hardcover. $49.95 speaks to their value and versatility in the land- scape. Yet perhaps the book’s strongest value is The late Father John Fiala was well known in its history of the events and people that have horticultural circles for his lifelong work to brought us the crabapple of today. improve lilacs and flowering crabapples. For a Father Fiala, also the author of Lilacs: The few years, his horticultural legacy endured in Genus Syringa, presents a highly personal per- the landscape of Falconskeape, his garden in spective on crabapple history. An inveterate Medma, Ohio, but ultimately preservation ef- breeder, he admitted that, "Like most hybridiz- forts proved unsuccessful. Fortunately, Fiala’s ers working over a lifetime, I am certain I have great devotion to crabapples has found more named too many crabapples, but, be assured, I lasting commemoration through the publica- have discarded a hundred times more!" In profil- tion of his book, Flowering Crabapples: The ing the key figures in crabapple breeding, Fiala dis- Genus Malus. cusses the commercial nurseries and university The crabapple, touted across much of the programs whose breeding efforts owe much to the " country as "America’s favorite flowering tree," wealth of raw material provided by the plant is valued for its adaptability to cold climates, exploration and introductions of the past century. ease of production, and great diversity of color This bounty has yielded a prolific and rather and habit. Defined as those taxa in the genus continuous stream of crabapple cultivars. While Malus that bear fruits 2.5 inches in diameter or in some genera, particularly roses, the release smaller, crabapple trees range in shape from of a new cultivar does not always signal an rounded to columnar and weeping, with flower improved or significantly "new" plant, many color extending from white to deep reds and recent crabapple introductions offer benefits to purples, and fruit from black-red to brilliant both the gardener and the ecological health of gold. Interest in developing a better crabapple the landscape. Indeed, crabapple breeders has, over the decades, led to an accumulation of deserve praise, for although imtially focused some 900 named varieties. The story of their on flower color, annual bloom, and other orna- development and landscape use, the subject of mental traits, they have, in recent decades, Fiala’s book, is of particular sigmficance to the responded to growing sentiment against the use Arnold Arboretum and other institutions with a of pesticides by developmg forms with increased long-standing commitment to crabapple display resistance to applescab, fireblight, and other and evaluation. diseases. Fiala’s book describes these breeding Clearly this handsome volume is much more efforts and resulting cultivars in encyclopedic a horticultural overview than a techmcal trea- fashion, offering information on their lineage, tise, and while some of Fiala’s taxonomic details attributes, and weaknesses, as well as providing may remain in dispute, the absence heretofore generous helpings of personal experience and of any color-illustrated, near-current guide to opinion. crabapples makes it a valuable contribution to As Father Fiala recounts, the Arnold Arbore- the literature. With separate sections on land- tum and other botanic gardens figure promi- scape uses, propagation, pests and disease, a nently in the development of the modern 35

’Don Wyman’ are among the significant cultivars developed at the Arboretum by Karl Sax, Wyman, and others. The publication of Fiala’s book gives occasion to revisit the progress of the Arnold Arbo- retum’s Malus collection. It is worth noting that the work of both Sargent and Wyman sur- vives today in the Arboretum’s collection of over 170 crabapple species and varieties. The collec- tion has been further enhanced by twenty years of systematic crabapple. While any discussion of crabapples evaluation ot disease resistance by the late Dr. in the United States would include mention of Lester Nichols of Pennsylvania State Univer- Arboretum horticulturist Donald Wyman, who sity. More recently, the Arboretum’s Living Col- did much to evaluate the performance of culti- lections staff has modernized and updated the vars and popularize the plant, Fiala also gives collection with 20 new cultivars that will be special notice to the work of Charles Sargent, evaluated for disease resistance and landscape the Arboretum’s first director: performance. Eventually, after sufficient trial and of the most the No horticultural institution did as much for testing promismg varieties, Arboretum will the best for introducing and discovering new species, variet- display crabapples ies or special clones as did the Arnold Arboretum southern New England. a ... Especially under Professor Charles Sargent, Fiala’s book would make fine companion for who took an active interest in crabapples, the a May trip to the Arboretum and is to be recom- Arnold Arboretum not only sought out new mended to those with a serious interest m the crabapple materials in Siberia and Japan, but it group. Any controversies within crabapple found also energetically promoted any crabapple circles over Fiala’s nomenclature overlook the in its gardens or elsewhere. larger value of this book as the chronicle of one Arboretum contributions include the tea of America’s preeminent horticulturists reflect- crab (Malus hupehensis), the Siebold crabapple ing on a lifetime of dedicated involvement with (M. sieboldii), and Sargent’s crabapple (M. one of our most important landscape plants. sargentii), which were collected by Sargent or his agents in Asia at the turn of the century. Richard Schulhof is Director of Education and Public ’Dorothea’, ’Blanche Ames’, ’Mary Potter’, and Programs at the Arnold Arboretum. 36

Arnold Arboretum Weather Station Data -1995

Average Maximum Temperature 60° Average Mimmum Temperature 40° Average Temperature 50° Total Precipitation 35.35 inches Total Snowfall 34.5 inches _ Warmest Temperature 96° on August 2 Coldest Temperature -2° on February 6 and 7 Date of Last Spring Frost 31 ° on May 2 Date of First Fall Frost 29° on November 5 Growing Season 207 days

Note: According to state climatologist R. Lautzenheiser, 1995 was a year for the record books. It was very dry with temperatures slightly above normal and sunshine slightly below average. January set a record with 13 consecu- tive days of measurable precipitation. However, this was followed by several months of below-average moisture levels. The combination of both March and April was the driest since March and April of 1966, and the fifth dn- est on record. April was also unusual because the temperature never reached the 60-degree mark at the Arnold Arboretum. June too was very dry, with only 50% of the normal rainfall for the month, makmg it the fifth dry month in a row. July followed as the sixth dry month in a row, settmg another record for the lowest amount of precipitation over this six-month period. The months of August and September continued the dry pattern by giv- ing us a 41-day period, from 8 August to 17 September, in which only .3 inches of precipitation was recorded. The drought broke on 17 September, the day of the Arboretum’s annual plant sale; on that day we received 2.32 inches of ram. This made September the first month since January with above-normal moisture. October set records for combined warmth and moisture, making it the warmest and wettest October on record. November continued the pattern of welcome moisture while also bemg the coolest November since 1980, with the least sunshine since 1977. December seemed to round off this peculiar year. It was very snowy, quite cold, yet on the dry side with normal levels of sunshine. The snowfall in December was more than three times the norm, making it the fifth snowiest on record. Oddly, the snowfall for the year was )ust average, the dearth of snow early in the year offset by the bonanza at the end. In the end, we found ourselves 6.40 inches below normal m precipi- tation for the year. Index to Volume 55 (1995) Numbers m parentheses refer to issues, those m boldface to illustrations of the entries

Acanthopanax (3/: 188 - - Weather Station Data, 1995 Caulophyllum thahctroides (3): 6 Acer (4~: 12 (4/: 36 Ceanothus, species and cultmars (1/:(: - damdm ( 1 /. 15, 18 ----- 1994 (1): 40 21-23; (4) : 26, 27, 29 " - diabohcum /4~: 8 "Arnold’s Promise Fulfilled," -amemcanus ’Roseus’ (1): 21, 22, 23 - gnseum ( 1 /: 9, 12, 14-16 James L. Jones (2) : 27-32 Cedrela sinensis /3): 177 - henry ( 1 15, 18 Aroma (3): 188 Cedrus hbani (4y 3 -mono /1/: 15, 17-18 Artocarpus altihs /3/: 12 Celastrus (3): 188 - palmatum (2/: 29 Asarum europaeum / 1 99 "Celebration of Crabapples: Book - rubrum (3/. 5-6 . Ash (3): 8-9 Review," Richard Schulhof (4) ‘ - saccharum (3)’ 5-6 - white (3) : 6 34-35 -tnflorum (1/:99 Asimina tnloba (3) : 12, 177 Cephaehs ipecacuanha (2): 6 Acomtum ( 1 15, 177 Aspen, quaking (3): 122 Cephalotaxus, culuvars and species Actimdia chmensis ( 1 ~: 177 Asperula mtlda puberula / 1 33 (1)~ 24-39 -dehciosa (3~: 18 - - ssp. hirtella (1) 3 - drupaceae ( 1 27, 28, 29, 30, 33, Adiantum pedatum ( 1 ~:8 Asplemum ceterach ( 1 10 36,37

- -- var. aleuticum ( 1 6G - tnchomanes ( 1 66 fortunei ( 1 /~ 28, 29, 30 --var subpumilum (1/~ 6 Atropa mandragora (2) : 4 - harnngtoma / 1 25, 28, 30-33, 37 Adiantum venustum ( 1 55 Azalea (3)~ 188 - koreana / 1 30, 31, 32, 33, 37

- Aesculus hippocastanum (4~: 12 - torch (4/: 12 olmem ( 1 27, 29, 31, 33-34, 37 -parmflora (2/: 29; (3~: 188 - sinensis ( 1 )~ 15, 24, 26, 28, 29, 30, - turbmata (4) : 13, 14 Bard, Samuel (2): 22 34,37 Aethionema oppositifolmm (1~: 6 Bartram, John (2y 19, 21-23 "Cephalotaxus~ The Plum Yews,"" Ailanthus alussima (3~: back cover, Bartram, William (2) : 22 Kim E. Tmpp / 1 24-39 177 Basswood (3) : 6-7 Cercis glabra / 1 ). 188 Akebia qumata ( 1 177 Bayberry (4): 26, 29 Cercocarpus (4) : 27 Albizia tulibnssm (2~: inside back - southern (4): 26, 28 Chaenomeles (3) : 188 cover; (3~: 177 Beauty berry ( 1 188 - ~apomca (4)~ 7, 8 --’Rosea’ (2) : 28, 30 Beauty bush ( 1 188 -speciosa ’Nivalis’ (4)~ 8 Alchemilla molhs ( 1 99 Beech (3). 2, 6-10 Chamaecypans (1): 7 Alder (3) : 7; /4~: 16-30 - American (3)’ 6, 12 Cherry, autumn-flowemng (4/~ 8 Alnus, culuvars and species (4) 16- Berbens (3) : 188 - Takane (4) : 8 25 ; 27, 29 Betula lenta (4) : 12 - weepmg (4) : 8 - acummata var. mulnnerms (4/: Bignonia capreolata (3) : 18 Chinese medicine, traditional (2) : 18,21,22 Botrychmm vmgmianum (3). 6 12-18 - hirsuta (4): 16,19-24 Broussonettia papynfera (3): 177 Chionanthus retusus (11: 9; (4) 13 - ~apomca (4~: 18-19, 22, 23-24 Bumeha languinosa (4): 13 Cimicifuga (1): 9, 155 Ambrosia (2)’ 25 Bussewitz, Al, photo by (2): back - acerma ( 1 177

- - artemisifoha (2~. 25 cover simplex ( 1 ): G1 Amelanchier (3/. 177 Butterbur, large-leaved / 1 33 Cmchona (21: 13 Amorpha (3/: 18 Buxus sempervmens ’Vardar Valley’ - officmahs (2) : 6 Androsace (1/: 3, 6 (2) 32 Cladrasus (3) : 177 -’Mrllstream’ ( 1 100 Claytoma vmgmica ( 1 55 Anemone / 1 99 Cailiang, Mao, et al., "Plant Clematis /1/: 2; /2/: 25; (3/: 18 . - qumquefoha / 1 ~:5 Collecting on Wudang Shan" / 1/: -recta (2)~ 32 Anemonella thahctroides (1/: 10 12-20, 13 - vmgimana (2) : 25 Araha (3/: 13; 18 Callicarpa japonica ( 1 ). 188 Clerodendrum (3)~ 188

- - cahformca (4~: 13 Camelha (3): 18 tmchotomum (1): 15; (2) : 28, 29, Araucana cunmnghamia (3~: 13 Campsis radicans (3/: 18 30 Ansaema ( 1 4, 155 Caragana (3)’ 188 Clethra (3) : 13 - consangmmum ( 1 /. 177 Cardamme pentaphyllos ( 1 ).4 -almfoha /3): 18; (4): 3, 12 - sikokianum ( 1 10, 111 Cardiocrmum cathayanum / 1 ): 177 Clethropsis /4): 188 Anstolochia (3~: 188 Carya (3): 17; /4): 11-12 Clmtoma /1) 4 Arnold Arboretum ( 1 3, 7, 9, Cassia marilandica (2)’ 32 Colden, Cadwallader (2): 19, 21-23 12, 19, 22-23, 25, 31, 33, 37; Castanea henry (1). 188 Colden, Jane (2). 19-26 (2/~ inside front cover, 8, 12, 15, Casuarina (4). 27-29 Collinson, Peter (2) 19, 21-22 16, 17, 27-32; (3).inside back -eqmsetifoha (4). 30 Comptonia peregnna (3) 13, 18; (4) : cover, 3, 13-14, 22-24; (4) 2-15, Catalpa (3): 177 26,27,28,29 5, 9-11, 13-14, 23-24, 34-35 Catharanthus roseus /2): 7 Comfers, dwarf / 1 6, 7 38

Connor, Sheila, "Mystical, Medici- Ellis, John /2): 19, 23-24 Gmgko biloba ( 1 34, (2): 13; (3): 13 nal Witch Hazel" (3) : 20-21 Emmenopterys henry ( 1 ): 177 Glaucidmm palmatum (1): 4, 5 Conrad, Kevin, et al., "Plant Enkianthus perulatus (4)’ 13 Gleditsia triacanthos (3): 177 Collecting on Wudang Shan" ( 1/: Ephedra simca (2): 14 Glorybower (1): 15, (2): 29 12-20, 13, 16G Ephedrine (2): 144 Gronovius (2)’ 21-24 Copus (2): 24 Epimedmm ( 1 9, 15 Gymnocladus dioicus (3/~ 177 Cork tree (3): 23-24 - stellatum ( 1 15 --Amur (3/: 22 Engeron compositus ( 1 66 Halesia /3/: 177 Cornus /3/: 188 Erythromum ( 1 44 Hamamehs molhs (1/: 155

- - controversa ( 1 /~ 155 - amencanum (1): 5, (2): 25 vmgimana (3): front cover, 20-21; - flonda (2/: 28 Erythroxylum coca (2): 6 (4): 13 - kousa / 1 /: 9, 14, 15; (2)’28 Eucommia ulmoldes (2): 12-18, 14, Hangzhou Botanic Garden (2): 14, 177 - racemosa (3) : 5-6 15 "Hardy Asian Alders," Kim E. Tmpp Corylus avellana ’Contorta’ (4): 32- Euonymus (1). 18; (3): 177 (4) : 16-25 33 - bungeanus v. semipersistans /4): 8 Harnson, Mary, "Jane Colden: -maxima (3): 18 -eleganussima (1). 188 Colomal American Botamst" (2) : Counus (31: 18 -hamiltomanus ssp. sieboldianus 19-26 Cotoneaster dmamcatus (2) : 30 (2) : 30 Harvard Forest, Petersham, MA (4): Crabapple (4) : 13, 34-35 - yedoensis (2): 30 23, 28 Crataegus (3J 177 Evodia (3): 17 Helleborus (2): 24 -laemgata (3) : 14 Helomas bullata ( 1 44 - punctata (3/: 13 Fagus grandifoha (3/: 6, 122 Heptacodmm micomoides ( 1 9; (2): Cunninghamia lanceolata (1) back Fatsia (3): 188 30 cover Faxon, C. E , drawings by (4/~ 19 Herbarium Bogoriense, Indonesia Cydoma oblonga /3) 177 Fern, Chnstmas (3): 6 (2): 8-9 Cynlla racemiflora (3): 188 - grape (3)’ 6 Hevea brasihensis (2/: 155 Cystopteris bulbifera f. cmspa (1/: 6 - ostrich ( 1 99 Hickory (4). 11I - spmulose wood (3): 6 Hippocrates (2) 3-4 Dacrydium zanthandrum (3): 13 - sweet (3): 13; (4) : 26, 27-29 Hippophae rhamnoides (3/: 18; (4/: Daphne ( 1 9; (3 /: 188 Fiala, Father John (4): 34-35 29 -alpma (1): 3 Ficus canca (3): 177 Holt, Saxon, photo by ( 1 front - arbuscula (1) G6 Fir, China / 1 back cover cover

- - cneorum ’Eximia’ ( 1 33 Douglas (4): 29 Honeysuckle, narrowleaf Standish Decaisnea fargesm (1/: 15; 18 - ~omt (2). 3, 14 (4/:8 Del Tredici, Peter, "Requiem for a - three-pomted / 1 ): 29 Horsechestnut (4). 12 Cork Tree," (3/: 22-24; "Shoots Fordham, Alfred ( 1 3; (4): 4 - Japanese (4). 13 From Roots: A Horticultural Forrest, Todd, "Two Thousand Hubei Province, China (1). 12-20 Review" (3): 11-19; "A Nitrogen Years of Eating Bark: Magnolia Hull, Catherine, "Uplands: Life Fixation: The Story of the Frankia officmahs var. biloba and Among the Alpines" ( 1 2-11, 9 Symbiosis" (41: 26-31; photos by Eucommia ulmoldes m Tradi- Hurricane of 1938 (3/: 3; (4): 4-5 ( 1 back cover; (3 inside front tional Chinese Medicine" (2): 12- Hutchinsia alpma (1/: 6, 7 cover, back cover; (4): cover 18 ; "Nature’s Vagaries The Hydrangea quercifolia (3/: 188 - - et al., "Plant Collecting on Weather of 1995 and the Living Hypemcum ( 1 18 Wudang Shan" ( 1 12-20, 13 Collections" (4) : 2-15 -calycmum (3) 188 Dentama diphyllum (3) : 6 Forsythia /3): 188 - vmgmicum (2): 23 Digitahs purpurea (2/: 133 - giraldiana ( 1 ): 155 Diospyros lotus (1/: 188 Fortunana sinensis ( 1 177 Ilex (3/: 188 Dodecatheon maedia ’Album’ Foster, Lmcoln ( 1 ): 2, 5 -perny (1/: 15 (1/:4,55 Fothergill, John (2). 19, 23-24 Ilhcmm flondanum (3) : 188 Dogwood, Chinese pagoda ( 1 155 Fothergilla (3) : 188 Imperial Botamc Garden, St. - flowering ( 1 22 - gardenm / 1 99 Petersburg (3) : 22 - gray (3 5-6 -ma~or (1): 9 Indigofera /3/: 188

- - kousa / 1 144 Frankia (4): 26-29 pseudotmctoma (2/: 31-32 Dryoptens austnaca var. spmulosa Franklma alatamaha (4) : 8 Indonesia, Arnold Arboretum’s (3/:6 Fraxmus amencana (3): 6 exploration in (2) : 8 Fringe tree, Chmese (4) : 133 Ipecac (2) 6: Ehret, George Dionysms, drawing Ipomoea purga (2). 6 by (2) : 20 Garden, Alexander (2): 19, 22-23 Elaeagnus (3) : 18; (4): 29 Gardema (3): 188 Jack, J. G. (4): 3, 7 - an~tMtj/oJja (4): 27, 30 -7asmmoides (2): 23 "Jane Colden: Colonial Amencan - pungens ( 1 /: 155 Gentiana acauhs (1): 6 Botanist," Mary Harnson (2): 19-

- - umbellata (4): 27 scabra ( I 55 26 Elliottia racemosa (3) : 177 Gerard, John (2)~ 4 /asmmum nudiflorum (4) : 8 39

John Evelyn (3): 11-122 Malus (3~: 17; (4~: 13, 34-35 Orixa ~apomca (21 27; (3/~ 18 Jones, James L., "Arnold’s Promise - hupehensis /4~: 35 Fulfilled /2/: 27-32 - sargentn (4) : 35 Paeoma obovata var. mllmottiae Judd, William (4) : 4 - sieboldm /4/: 35 ~1/~ 177 Maple (3): 2, 8-9 -suffruticosa (2) : 311 Kalmiopsis leachiana ’Umpqua - Japanese (2~: 29 --’Joseph Rock’(2): 311 Valley’ / 1 3, 4 - paperbark ( 1 12, 14-16G Pahurus ~3/: 188 Kalopanaxpictus /3/: 177 - red (3): 5-6 Panax gmseng /2/: 144 Koelreutena pamculata ~3/: 177 - snakebarked / 1 /: 155 - qumquefohus ~2/. 144 Kolkmtzia amabilis (1): 188 - sugar (3): 5-7 - trifolius (21: 24 Koller, Gary, "Rehder’s Ceanothus: Marks, P. L., "Readmg the Land- Papaver alpma ~ 1 /:8 Ceanothus x palhdus ’Roseus"’ scape : Primary vs Secondary Paulownia tomentosa (3). 17; 4): 10 ~ 1 /: 21-23 Forests" (3)’ 2-10 Pawpaw (3) : 12, 177 Matteucia struthiopteris ( 1 ~:9 Peony, tree (2): 311 Lagerstroemia mdica ~3/: 188 McDonald, J Andrew, "Medicinal Pepperbush, sweet ~4y 12 Laurus nobilis ~3/: 17 Plant Exploration-Past and Periwinkle (2) : 7 Lautzenheiser, R. E. (4) : 6 Present" (2~ 2-11; photo by (2): Persimmon, wild ( 1 188 Lelophyllum buxifolmm var. front cover Petasites hybmdus ~1/: 3 prostratum 1 /:3 "Medicinal Plant Exploration- Phellodendron amurense (3/: inside Leitnena flomdana (3) : 18 Past and Present," J. Andrew back cover, 17, 22-24 Lespedeza thunbergm (1). 9 McDonald (2)~ 2-111 Phoebe bournei ( 1 15 Lemsia ~ 1 /:3 Mehosma /3) 18 Phouma / 1 188 - brachycalyx / 1 88 Mentha /2~: 28 Physoplexis comosa (1). 10 Ligulana /1/: 15; /2/: 31 Meyer, Paul, et al., "Plant Collect- Phyteuma orbiculare ~ 1 /:8 - dentata (1/: 166 ing on Wudang Shan" ( 1 12-20, Phytolacca ~2/: 24 Lilac, Pnncess Mane ~4/: 8 13, 19; photo by ( 1 inside front - amencana /2/: 24 Lmdera glauca 1 /: 15, 188 cover - decandra ~2/: 24 Lmnaeus /1): 21; (2): 7, 19, 21-22, 24 Mimosa (2y inside back cover Picrasma quassioldes (3) 177 Liqmdambar styraciflua ~3/: 11, 14, Moluccas (2). 8 Pme (3): 8 177 Monarda didyma (2)’ 25 - Australian (41: 27, 30 Lonicera / 1 /: 18; /3/. 5, 18 Morus (3) : 177 - ground (3) : 6 - fragrantissima ~2/: 30 Mulch / 1 10 - red (3) :3 -standlshm f lancifoha /4/: 6, 8 Mynca /3~: 13, 18; /4/~ 28, 29 - tabletop ( 1 144 Loropetalum chmense ( 1 /: 188 - cenfera (4~ 26, 28 - white (31: 6 Lycopodmm flabelhforme /3/: 6 -gale /4y 26 Pmus resmosa (3) 3 Lyoma ovahfoha ~ 1 /: 155 - pensylvamca (4/. 26 - strobus ~3/. 6 " "Mystical, Medicinal Witch Hazel," - tabulaeformis ~ 1 y 14 Maackia amurensis (3): 177 Sheila Connor (3) : 20-211 "Plant Collecting on Wudang Macleaya cordata (2): 32 Shan," Peter del Tredici et al. ( 1/: Maclura pomifera ~3/~ 177 NACPEC (North Amencan-Chma 12-20 Madsen, Karen, photo by (1). inside Plant Exploration Consortium)I Plant exploration, medicmal ~2/: 2-111 back cover ( 1 12, 199 Pokeweed (2): 24 Magnocuranne ~2/. 17-188 Nandma /3~: 18 Pohothyrsis sinensis /4/: 13, 14 Magnolia ashm (4) : 12 "Nature’s Vagaries The Weather of Polygala senega /2/: 25 " - frasem ~2/: 17; (4/: 13 1995 and the Living Collections," Polystichum acrostichoides ~3/. 6 -grandiflora (2/: 29 Todd Forrest (41: 2-15 Poncmus tnfohata (2). 28 - hypoleuca ~2/: 16 New Guinea (2) 7 Poppies, alpme ~ (1): 2, 6 - kobus (4/: 8 Nicotiana tabacum (2) : 6 Populus (3) : 11, 17; (4): 19 - macrophylla (2/: 17; (4/ 3, 12 "Nitrogen Fixation: The Story of the - tremuloides (3) : 122 -officmahs (2/: 16-177 Frankia Symbiosis, Peter Del Pnmula ~ 1 /:4 --var. biloba (2) : 12-18, 16, 17 Tredici (4) : 26-311 - denticulata (1/: 4 -sahcifoha (4) : 13 North American-China Plant - ~apomca ~ 1 111 - tnpetala (4) : 12 Exploration Consortium - kisoana ( 1 /:7 2014 vjr~jnjilM ’Milton’ 12): 29 (NACPEC~ / 1 12 - x ’Frances P K ’ ~ 1 44 Magnolia, anise (or willow-leaved) North Carolina State University Propagation (3): 11-19; (4y 23, 34-35 (4) : 13 Arboretum /4~: 32-33 Prunus (3) : 11, 17 - bigleaved (4): 12 Nyssa sylvatica (4): 13 - nipponica (4): 8 ’ - - Fraser ~4/: 133 subhmtella v ascendens ~4/. 8 - Kobus (4) : 8 Oak (3~: 2, 7, 24 - - v. autumnahs (41: 8

- - umbrella (4): 122 chestnut ( 1 144 Pterocarya /3/: 177 Mahoma aqmfolmm (2/: 311 Olive, autumn (4) : 27, 29 Pteroceltis tartmowm ~ 1 /: 177 - bealm / 1 177 Olive, Russian (4~: 27, 29, 30 Ptilotnchum spmosum ’Purpureum’ - japonica (2/: 30-311 Opuntia (2): 6 (1/:66 40

. Pueraria lobata (1). 177 Sassafras albidum (2~: 4; /3y 12, 15, Tsuga canadensis (3) : 6, (4) : 12 Purshia tndentata (4): 27 177 Tsusiophyllum tanakae ( 1 ~:6 Pyracantha coccmea (3): 18 Saxifraga longifoha / 1 ~:8 "Two Thousand Years of Eating Pyrus calleryana (31: 177 - pensylvamca ( 1 /:4 Bark: Magnoha of ficmahs var. Scabiosa lucida (1): 8 biloba and Eucommia ulmoldes " Qrfa, Zang / 1 12, 13 Schulhof, Richard, "A Celebration m Traditional Chmese Medicme," Quercus alba (4): 12 of Crabapples: Book Review" (4) : Todd Forrest (2~: 12-188 -ahena (1): 14 34-355 - serrata ( 1 188 Scott Arboretum, PA (3) : 15 U.S. National Cancer Institute (2): - suber (3) 24 Senna, native (2) : 32 7, 13 - variabihs ( 1 /: 14, 188 Sequoia sempermrens (3/: 13-14 Ulmus (3~: 11; (3) 17 Qumce, Japanese flowering (4) : 8 Shepherdia canadensis (4/: 27 - glabra /3y 20

- - Nivalis flowering /4/: 8 "Shoots From Roots. A Horticul- parmflora ( 1 /:6 Qmmne (2): 6, 13 tural Review," Peter Del Tredici "Uplands: Life Among the Alpines,"" (3) : 11-199 Catherine Hull ( 1 2-111 Racz & Debreczy, photos by (2): Silk tree (2/~ inside back cover inside front cover, inside back Smomlsoma henry /1/: 15, 177 Vaccmmm (1/: 9; (3) : 188 cover; (3~: inside back cover Smilax (2~: 6 - macrocarpon ’Hamilton’ ( 1 ~:3 Raup, Hugh /4~: 4 Snowbell, fragrant (4) : 122 Vancouvema hexandra ( 1 99 "Reading the Landscape: Primary Sohdago rugosa /3~: 5 Viburnum / 1 /: 9; (3): 18; (4): 12 - vs Secondary Forests," P. L. Sophora 7apomca (3~: 177 -- -acemfolmm (3): 6 Marks (3~: 2-10 Sorbana sorbifolia (3) : 18 - dentatum (3) : 6 "Rehder’s Ceanothus’ Ceanothus x Sorbus yuana (4) : 13, 14 - farren ’Candidissima’ (4): 7, 8 palhdus’Roseus’," Gary Koller Spicebush, Chinese ( 1 155 -rhytidophyllum /4~: 13 (1). 21-23 - evergreen ( 1 / 188 - x bodnantense ’Dawn’ (4~: 8 Rehder, Alfred ( 1 23, 34, 37; (2) : 16 Spmaea /1/: 18; (3~: 18 Viburnum, arrowwood /3 66 "Requiem for a Cork Tree," Peter - x arguta (4~: 8 - leatherleaved /4~: 13 Del Tredici (3~: 22-24 Spongberg, Stephen (1/~ 37; /4~: 6-7, -mapleleaf (3) : 6 Rhamnus cathartica (3~: 5 24 Viola vanegata ( 1 88 Rhizobmm (4) : 27-28 Staphylea (3) : 177 Violet, dogtooth (2~: 25 Rhododendron / 1 2, 18; (31: 18 Steele, Fletcher / 1 / 2-G -’Blue Peter’ (2)- 311 Stewartia (1)~ 9; /4~: 12 Waldsteima ternata (1~: 9 - calendulaceum (4~: 3, 122 - smensis ( 1 /: 14, 1 G-17, 18 Walking stick, Harry Lauder’s (4) : -maximum (2/: 311 Stewartia, Chinese ( 1 144 32-33 Rhodotypos scandens (3~: 18 Stolons (3/: 13 Weather Station Data, Arnold Rhus 18 obassia 12 Arboretum, 1994 ( 1 40 (3) : 13, Styrax (4/: 10, _ Ribes /3/: 188 Sweet gale (4) : 26 ----- 1995 (4/. 36 Ricmus commums (2) : 4 Sweetgum (3~: 111 Wilson, E. H. / 1 12, 17-18; 25, 34, Riming, Hao, et al., "Plant Collect- Sweetleaf, Chmese / 1 188 photo by 36, 37; (2~: 12, 15, 16; (4) : ing on Wudang Shan" / 1 12-20, 133 Symphoncarpos (3~: 188 17,24 Robinia (3) : 13 Symphyandra hofmannii (1~: 8 Wisteria (3~: 188 -hispida (3/: 18 - wanneri ( 1 10 Witch hazel (3): front cover, 20-211 -pseudoacacia /3/: 12, 17 Symplocos chmensis (1/: 188 tree (3): 20 Rock gardemng / 1 2-111 Syrmga meyen ’Palibm’ ( 1 ~:9 - - Chinese ( 1 155 Rodgersra ( 1 /: 9, 155 - vulgans ’Pnncess Mane’ (3): 188 Wudang Shan, China (1). inside Root cuttings (3) : 11-199 front cover, 12-20, 13, 18 Root suckers /3~: 11-14 Taxus / 1 25 Wyman, Donald (4~: 4, 6-7, 10, 35 . Rosa (3~. 18 - baccata (2)’ 13 -’Seafoam’ (4): 8 - bremfoha (2) : 7, 13 Xanthoceras sorbifohum /3/: 177 - foetida (2~: back cover Tea, New Jersey /4~: 26 Xanthorhiza simphcissima (3/: 188 Rose, Austrian copper briar (2y back Telekia speciosa (2): 311 cover Thomas, R. William, et al., "Plant "Year in Trees and Words: Book - hybrid tea / 1 22 Collecting on Wudang Shan" ( 1/: Note and Excerpt" (4~: 32-33 - seafoam (4) : 8 12-20 Yew, plum, species and cultivars ( 1/: Rubber tree, hardy (2) : 155 Thoreau, Henry David (3~. 1I 24-39 Rubus (3) : 15, 18 Tiha amencana (3/. 6 Yi, Lii ( 1 12, 13 Tmcertis macropoda ( 1 16 Sahx alba (2): 133 Tmllmm grandiflorum (1~: 10; (3/: 6 Zanthoxylum (3): 188 - arbuscula / 1 66 2014 2014 ’Flore Plenum’ (1): 5 - molle ( 1 155

- - hylematica ( 1 /:G recurvatum / 1 ):5 Zelkova serrata / 1 166 Sambucus (3p 18 Tmpp, Kim E., "Hardy Asian - smca ( 1 15-166 Sargent, Charles ( 1 37; (4~: 3, 8, 24, Alders" (4): 16-25; photo by (4) : Zizyphus ~u~uba (3) : 177 35 inside cover The Arnold Arboretum W I N T E R . N E W 5 . 1 9 9 5 - 1 9 9 6

A Wetland Restoration Robert E. Cook, Director The spring of 1996 will mark another milestone in the evolution of the landscape of the Arnold Arboretum. A 24-acre parcel of land known as the Stony Brook Marsh will be formally added to the grounds and incorporated into the park system of the City of Boston. It has been a century and a year since such an action was last taken. In 1895 the Peters Hill tract was placed under the original 1882 agreement whereby the Arboretum land was given to the After valuable of our educational City for parks and leased back to park system. years of political part and have efforts-for casual visitors and Harvard University as a center for legal maneuvering, they succeeded in a adult classes, but for our the scientific study of trees. reaching mutually especially beneficial arrangement between children’s educational program The Stony Brook Marsh is a the City and the Arboretum. with local schools. In this low-lying area of wetland vegeta- special In for the sense, it will be of the tion marking the merger of taking responsibility symbolic of the Brook vision that led Charles Bussey Brook into Stony Brook. It management Stony Sprague Marsh, the Arboretum will com- and the fathers to separates the south flanks of Hem- Sargent City lock Hill and Bussey Hill from mit itself to restoring the habitat form the original partnership for to a more natural wetland condi- of Boston over a the Forest Hills subway station the people tion. It will become an and rail tracks leading to Dedham. immensely century ago. Onginally part of the Bussey Insti- tution of Harvard University- Native Native Trees one of the first agricultural People, colleges in the country-the land As part of a new Arboretum field children’s interest in both trees has been abused and has fallen study, Boston-area children will and Native Amencan culture. into decay over the past half cen- soon explore the meadows and Developed in collaboration tury. It became a dumping ground comfers of Bussey Brook valley to with local schoolteachers, the pro- for refuse, and its higher ridges discover how Native Americans gram shares much of what we were invaded by a heavy growth of denved vital sustenance from the know about the relationships that weedy shrubs and trees. northern forest. The program, once existed between Native A decade ago, local friends of "Native People, Native Trees," Americans and the land known the Arboretum formed the Arbore- began in 1994 when Arboretum today as the Arnold Arboretum. tum Park Conservancy and took on field study coordinator Annette Thanks to a field reconnaissance the goal of incorporating this ur- Huddle set out to create field survey conducted by Boston city ban wild into the lease agreement activities for grades three through archaeologist Steve Pendery, we with the City as part of the Boston five that would encourage know that Native Amencan occu- pation of a site near the Arbore- tum’s Bussey Brook began nearly 8,000 years ago and continued sporadically up until the time of European colonization. "Native People, Native Trees" revisits this era and enables children to con- sider the challenges faced by the Arboretum’s earliest inhabitants through a search for white cedar, white birch, and other species that were critical to human comfort and survival. With pilot testing of the pro- gram now complete, we look for- ward to introducing the study to schools later this year. We thank the Massachusetts Cultural Coun- cil for their support of the project. Annette Huddle leading a storytelling session on Hemlock Hill.

New Staff

and is currently enrolled in the M.S.L.I.S. program at the Simmons College Graduate School of Library and Information Science.

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Elizabeth Kolster joined the Arboretum in December as an information systems project man- ager working with the biodiversity conservation project in Southeast Asia. Liz will be developing a national biodiversity database sys- tem for the Government of Indo- nesia, and she bnngs extensive Carol Mita has joined the Botany expenence with computers to the graphical information systems Libraries staff as Serials Manager. project. She has worked as director that combine map-based informa- She is responsible for all incoming of information systems at Boston tion with data on critical natural serials, bindery operations, and the University and for the Faculty of resources, such as the biodiversity serials exchange program. Carol Arts and Sciences at Harvard. She of developing countries in tropical has held other serials and catalog- is particularly interested in geo- Asia. Liz is also an avid sailor. ing positions in the Memorial

~ ~ , Library and the Middleton Health Sciences Library of the University Error Noted: In last issue’s "Cork Tree’s Last Hurrah Provides a of Wisconsin, Madison. She received Science Lesson on Leverage," the Resistance Force should have the B.A. in zoology from the Uni- read as 7,763 pounds (or 3.9 tons). versity of Wisconsin, Madison,

© 1996 American Landscape Lecture Series

This winter marks the fourth year of collaboration among the Arnold Arboretum, Olmsted National His- toric Site, the Harvard Graduate School of Design, and a number of other sponsors to present a lecture series exploring our changing relationship with the Amencan landscape. This year’s series, Memory in Place, examines landscapes, museums, and literature that seek to com- -J memorate and encourage reflection about the places, figures, and events of our collective past. The Arbore- tum extends its thanks to the Massachusetts Foundation for the Humanities for its special support of the series. are at in at i~ All lectures free and begin 6:30 pm the Piper 48 Quincy Street, Cambndge. For mformauon, call Auditorium of the Harvard Graduate School of Design the National Park Service at 617/566-1689 x 220. Thursday, February 22 The Power of Place. Urban Landscapes as Public History Dolores Hayden, Professor of Archztecture, Urbanism, and Amerzcan Studies, Yale ZJnzverszty Wednesday, March 6 Preserving Memory: The Making of the United States Holocaust Memorial Museum Edward T. Lznenthal, Professor of Relzgzon and Amerzcan Culture, Unzverszty of Wzsconszn Thursday, March 14 - The Invention of Place: Environmental Perceptions m American Literature Lawrence Buell, Professor of Englzsb, Harvard Llnzver~zty ,,, Tuesday, April 2 The Garden as Narrative: Lawrence Halpmn’s Franklm Delano Roosevelt Memorial . Reuben M. Razney, Professor of Landscape Arehztecture, L7nzverszty of Vzrgznza .,.. Monday, April 8 Memory Gardens: The Poetry and Gardens of Ian Hamilton Finlay _ Alec Finlay, Poet, Edinburgh, Scotland

Free Tours at the Arnold Arboretum I Willows, cherries, magnolias, dogwoods, crabapples, lilacs, roses, mock oranges, hydrangeas, and many, many more plants will be highlighted on free monthly walking tours at the Arnold Arboretum. These tours will be offered March through September, on the fourth Saturday of each month, beginning at 10:30 am on the front steps of the Hunnewell Building and lasting approximately an hour. For further information, or to find out if a tour has been canceled due to weather, call our general information message at 617/524-1718 x 773. date hzghlzght March 233 witch hazels and willows April 27 Arbor Day: great trees of the Arnold Arboretum May 255 dogwoods and lilacs June 22 roses and mock oranges July 27 bottlebrush buckeye ’ August 24 oakleaf hydrangea and scholar trees 28 franklinia and witch hazels September ,

© 1995-1996 Annual AppealI Lisa Hastings, Senior Development Officer Arnold Arboretum members and friends are responding generously to the 1995-1996 Annual Appeal, with a total of $54,159.91 in gifts received to date. In his letter seeking annual support, Director Bob Cook reflected on the recent passing of the 125-year- old Amur cork tree. The tree died when a group of local schoolchildren climbed onto a low-lying limb for a photograph. Over time, the cork tree had come to symbolize in a unique way the many facets of the Arnold Arboretum-as scientific institution, public park, and historic landscape. As one of the Arboretum’s oldest trees, its accession number was recorded by Charles Sprague Sargent in 1874 when it arrived in the form of dry seed from the Ruusan Imperial Garden of St. Petersburg. During its long life, the tree came to be loved by children of all ages. "The generous support received from our members is most appreciated," says Bob Cook. "The Arboretum has always meant different things to different people. Gifts to the annual appeal represent a strong vote of " confidence in our commitment to grow and curate an exceptional collection of trees."

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The Arboretum’s Education Department offers a wide variety of courses, programs, and lectures in horticul- ture, botany, and landscape design. A selection of spnng and summer courses is shown here. For a complete catalog of programs and events at the Arboretum, please call 617/524-1718 x 162. Note that fees shown in boldface are for members of the Arboretum. For information about becoming a member, call 617/524-1718 x 165. ~.

.<i HOR 498 The Collector’s Garden: WAL 168 Private Gardens of Designing with Extraordinary Plants England and Wales Ken Druse, Author and Photographer Daphne Foulsham, Chair, Natzonal Gardens Scheme In this slide-illustrated lecture, Ken Druse will take Sit back and enjoy an armchair tour of rarely us on a journey to memorable gardens and introduce seen private gardens in England and Wales. Mrs. some of the people and plants that will be shaping Foulsham’s slides capture a diversity of gardens, the direction of gardening in the 21st century. ranging from cottage and country gardens to his- Fee: $15, $18 torical landscapes and sophisticated town gardens. Friday, April 12/ 7:30-8:30 pm Fee: $12, $155 (State Laboratories) Tuesday, April 23/ 7:00-8:00 pm (HB)

Lilac Sunday, May 19,1996 There are thousands of flowering plants to admire in the Arboretum, but only one, the lilac, is singled out each year for a daylong celebration. On Lilac Sunday garden enthusiasts from all over New En- gland gather at the Arboretum to enjoy picnicking, watch Morris dancing (English folk dancing), take tours, and purchase lilacs. On the day of the event the Arboretum will be open from dawn to dusk with lilac plants and refreshments available for pur- chase from 10 am to 4 pm. For information, call the Arnold Arboretum at 617/524-1718 x 100.

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