Bulletin of the American Rock Garden Society Volume 51 Number 2 Spring 1993 Cover: Gentiana sino-ornata by Jill S. Buck of Westminster, Colorado All Material Copyright © 1993 American Rock Garden Society \ Bulletin of the American Rock Garden Society Volume 51 Number 2 Spring 1993 Features Asarums, by Barry R. Yinger 83 Ancient Rocks and Emerald Carpets, by Jeanie Vesall 93 The Diapensia Family, by Stephen Doonan 101 The Southeast Asia-America Connection, by Richard Weaver, Jr. 107 Early Editors of the Bulletin, by Marnie Flook 125 From China with Concern, by Don Jacobs 136 Departments Plant Portraits 132 Propagation 145 Books 147 u to UH 82 Bulletin of the American Rock Garden Society Vol. 51(2) Asarums by Barry R. Yinger Until very recently, few American of old Japanese prints, my interest went gardeners displayed interest in the from slow simmer to rapid boil. I subse• species and cultivars of Asarum. When quently spent a semester in Japan, my own interest in this group began to where my interest became obsession. I develop 20 years ago, there was little have since learned a great deal about evidence of cultivation, even among these plants, particularly during my avid rock gardeners. Some American research in the Japanese literature for species were grown by wildflower my thesis in the Longwood Program, a enthusiasts, and pioneers of American graduate course in public garden admin• rock gardening such as Line Foster and istration. As I make more visits to Harold Epstein were sampling a few of Japan, I continue to assemble an ever- the Japanese species. There was virtu• larger collection of Asarum, as well as ally no accurate information available information about them, their history, about the taxonomy or horticultural and their cultivation. requirements of the group. Species of Asarum are found wild I first became aware of Japanese only in an irregular belt around the Asarum as a college student, after temperate and warm-temperate regions reading one of Dr. John Creech's of the Northern Hemisphere. Within accounts of Japanese plants in Japan. this belt, glaciated regions have few He observed that on Yakushima, a species, while areas that escaped horticultural treasure island off the glaciation often have many. In North south tip of Kyushu, plants that one America, Europe, and Asia, interest in expected to be large were often very Asarum seems to pre-date written small, and plants that one expected to history. The native peoples of all three be small were sometimes surprisingly continents believed that Asarum large, as in the case of A. yakusi- possessed special medicinal or magical mense (now A. hirsutisepalum, photo powers. Korean shamans decorated p. 122). When one of my professors, their belts and headdresses {chokduri) the late Dr. Robert Baker, showed me with Asarum (chokduri-pul). In Japan, illustrations of Asarum plants in a book Asarum plants were hung under eaves 83 of buildings to protect them from earth• flowers' three lobes are calyx lobes. quakes and storms. Asarum still is Asarum flowers rarely have petals; if planted at the entrance of the grand they do these are vestigial structures shrine at Ise, the most revered shrine of well-hidden inside the flower. Shinto. In Europe, asaribacca The great majority of Asarum (Asarum europaeum) became part of species are Asian. There is only one the Materia Medica. Asarum continues species native to Europe (A. to be an important part of traditional europaeum). There are currently 15 Chinese medicine, a role it has played species listed for North America, 4 in since ancient times. the Northwest, 10 in the Southeast, Interest in the ornamental aspects of and 1 throughout the Midwest and Asarum also pre-dates reliable histori• Northeast. Only A. canadense is widely cal accounts. By the sixth century, dispersed in areas that have been thor• Japanese were using decorative oughly glaciated. Asarum designs on buildings (probably There is a remarkable concentration an evolution from the practice of using of species in southern China, mostly the actual plant for protection), and in between the Yangtze River and the time a series of decorative family crests Vietnam border, the presumed original {kamon) evolved. When the Tokugawa center of Asarum distribution. There shoguns adopted the Asarum mark, it are more than 30 species in China, became the most potent symbol of including Taiwan. Another concentra• power in Japan for over 300 years. By tion is in Japan, where again more the 1700s the practice of growing than 30 species occur. The Japanese selected Asarum mutations in decora• Ryukyu Islands (once mountains on the tive pots was a popular and highly Chinese coast) have more than 15 developed hobby among the samurai species closely related to both Japanese and wealthy commoners. Passionate and Chinese species. There are two interest in growing Asarum species and species in northeastern China, two in cultivars continues unabated in Japan. Korea, and one across the Himalayan At first glance the more than 100 Mountains to India. species of Asarum seem very similar, Native provenance is a rough guide to and many lack obvious ornamental hardiness. The most tender species are merit. On close inspection, however, those along the China—Vietnam border. their many differences and distinctive There is a general and rather consistent charm become evident. The basic increase in hardiness paralleling distance Asarum pattern is a low-growing, from this center of distribution. herbaceous perennial with heart- In the wild, asarums are woodland shaped leaves on stalks held on a plants, often growing in very deep creeping stem growing at or just shade. They commonly grow in small beneath the surface of the soil. Most valleys and ravines and on north-facing species are evergreen, a few are always hillsides. They are not thwarted by deciduous, and some go either way, intense root competition. I have seen depending on the severity of winter colonies thriving in bamboo thickets weather. The flowers emerge from the where little else could survive. Most rhizome at ground level. The more Asarum species grow exclusively on common shape is cup- or bell-shaped, relatively undisturbed sites; few re-colo• but quite a few have a "Dutchman's nize woodland that has regenerated pipe" flower, reminiscent of Aris- after farming or other major disruption. tolochia, one of their relatives. The Only a few species grow on somewhat 84 Bulletin of the American Rock Garden Society Vol. 51(2) dry sites; most are common near Asarum Species Worldwide streams or where seepage provides c o a consistently moist soil environ• n ment. Asarums are attacked by very SDAZ >ergree few organisms and are very perma• w P »- a> nent under stable, suitable condi• o c 3o tions. cj 3 -a r-C North America o Taxonomy Southeast Q w The genus Asarum was estab• A arifolium var. arifolium E 6 lished by Linnaeus in 1753, and A arifolium var. callifolium E 6 itchy taxonomists have been pulling A arifolium var. ruthii E 5B and poking at it ever since. Over the A contractum E 6 years, Hexastylis, Heterotropa, A heterophyllum E 5B Asiasarum, Japonasarum, and A lewisii E 6 Geotaenium have been proposed, A minor E 6 rejected, and proposed again by A naniflorum E 6 evidently under-employed tax• A rhombiformis E 6 onomists, who unsuccessfully judge A shuttleworthii var. harperi E 5B the integrity of this large group of A shuttleworthii \sr. shuttleworthii E 6 plants by examining a small A speciosum E 6 geographical grouping. The blind A virginicum E 5 man and his camel are still at it, but Northwest opinion is swinging decisively toward A caudatum E 6 the maintenance of one genus: A hartwegii E 6 Asarum. Even the Chinese, the A lemmonii E 6 world's master splitters, now accept A wagneri E 6 the integrity of the genus. Still, the Northeast and Midwest world is not safe; as in The Night A canadense D 4 of the Living Dead, the gardener no Ryukyu Islands sooner relaxes than some dormant A asperum var. geaster E 8 taxonomist with a sharp knife rises A celsum E 8 from sleep long enough to carve up A dissitum E 8 this group of very similar plants. A fudsinoi E 9 In spite of, or perhaps because of, A gelasinum E 9 the apparent similarity of the species, A gusk E 9 Asarum taxonomy is very complicat• A gusk var. minor E 9 ed. The great majority of Asarum A hatsushimae (=A. turbinatum) E 8 species were not even described until A lutchuense E 8 the 1900s. The process of resolving A monodoriflorum E 8B problems of identification and A okinawense E 8 nomenclature is compounded by the A pellucidum E 8 fact that the most important charac• A senkaku-insulare E 8 teristics for classification are inside A simile E 8 the Asarum flower. When the fleshy A tokarense flower is pressed, the result is much (=A yakusimense var. glabrum) E 7B like a freeze-dried road kill—unappe• A. trinacriforme E 8 tizing and difficult to reconstruct in A yaeyamense (=A hayatanum [?]) E 8 three dimensions. continued... Asarums 85 The result of this confusion is that most of the United States to grow are many Asa rum names are in flux. Even some of the native American species. if you can figure out which plant is The 10 evergreen species in the South• which, chances that the name is east are much hardier than their prove• permanent are not good. I rarely nance would suggest; most do well in receive a correctly named plant, and USDA Zone 5b or 6. Nursery-propagat• even after identifying a new plant, I ed plants of several are available occa• write all labels in pencil.