The Journal of the South Carolina Native Plant Society Spring 2011 Declining Shoals Spider Lily In this issue Populations in the Savannah River Spider Lily ..................... 1 (You know, that boundary between Georgia Bradford Pears ............... 2 Laurel Wilt .................... 5 and South Carolina). Lespedeza in the Carolinas .7 Drs. Judy Gordon and Donna Wear The Hickories ................. 8 Augusta State University Frank Holleman Receives For several years, the authors have been examining the decline of popula- tions of state protected Shoals Spider Lily, Hymenocallis coronaria, in the Au- Governor’s Environmental gusta Shoals area of the Savannah River, where it was first discovered in 1773 by Awareness Award famous naturalist, William Bartram. We recently published our research in the In recognition of his outstanding January 2011 issue of Natural Areas Journal, and here we share our findings with contributions to the protection, conser- SCNPS members. vation and improvement of the state's Background: Populations of this aquatic lily are declining throughout its natural resources, Upstate Chapter southeastern range in Alabama, Georgia, and South Carolina. Several inves- board member Frank Holleman recently tigators have suggested factors that could possibly contribute to the decline of received the 2010 South Carolina Envi- the Augusta Shoals populations, including river flow rates, sedimentation, water ronmental Awareness Award. Frank's quality, and herbivory by leadership was instrumental to the deer and aquatic ani- success of the Blue Wall Connection, mals such as beaver and which links lands in the Saluda water- muskrat. We knew that shed with conservation properties across a population on Stevens the state's Blue Ridge escarpment. Creek, a tributary of the Frank was also a driving force rallying Savannah River, was do- over 1000 private donors, state, city and other organizations to protect the ing well (See Fig. 1) so we environmentally sensitive and culturally decided to compare the significant Stumphouse Mountain from two habitats. We exam- development. He has worked closely ined many parameters, with the SC Department of Resources including a lot of animal and the US Fish and Wildlife Service scat, water quality, produc- to help protect the endangered bunched tion of flowers and seeds, arrowhead and Miccosukee gooseberry, clump size, and flow rate and to educate others to that need. The records (both actual and SC Native Plant Society is proud to US Geological Survey) claim Frank as our own, a true steward from 1892 to 2007. We with dedication, creativity and a talent also examined historic for bringing together citizens, conserva- maps from the US Army tion organizations and governmental Corps of Engineers (US- What the excitement’s all about! Photo courtesy of agencies to protect ecologically and Judy Gordon culturally sensitive lands. (See Spider Lily, page 4) South Carolina Native Plant Society • Spring 2011 1 Bradford (Callery) Pear: An Invasive Plant Problem By Bill Stringer Like most of us, Bradford pears have a dark side....... 2) Bradfords are known to have few insect herbivores, so a dense thicket of them produces very little biomass of native cat- erpillar and other insect larvae. “Well, that’s wonderful”, you might say, but you’d be wrong. A strong connection has been established between the amount of insect biomass produced on a landscape and the breeding suc- cess of songbirds on the land- scape. Caterpillars and other insect larvae are the staple food needed to grow songbirds to maturity. Adult songbirds have to work really hard to find enough food for their babies in areas with low density of insect larvae. What kinds of plants Figure 1. A swarm of Bradford pear seedlings developing in a stand of native grasses. They arose from produce insect biomass? The the clump of landscape trees in the background. Photo courtesy of author. answer is: native trees, shrubs, vines and herbaceous plants. Bradford Pear (Pyrus calleryana) be dense populations of young pear Introduced species like Bradfords has endured a long history of am- seedlings (see Figs. 1 and 2) which have low numbers of insect species bivalence. Its huge show of white can quickly become a large thicket in that can reproduce on them. Thus flowers in early spring has made it a areas that are not mowed at least an- a dense planting of Bradford pears very popular landscape tree in home, nually. If not mowed, the fast grow- will be an empty plate for breeding urban and industrial site landscapes. ing seedlings will become a dense songbirds. The diverse native plant But then, its weak stem and branch “forest”. community that was displaced by structure create huge splitting prob- “Well, what’s wrong with that?” pears would be a much better habitat lems in our occasional winter ice you might ask. “Won’t that be a for breeding songbirds storms, when folks have to saw it up spectacular sight in early spring?” 3) Seeds from the thornless and haul it away. However, Pyrus Maybe, but there are actually several Bradford trees used in landscaping calleryana has a third side which severe problems that arise from such actually produce seedlings with long, makes it a very poor choice for our a development: sturdy, woody thorns (See figure 3). landscapes. It is proving to be highly 1) The dense cover of pear trees So the trees that develop from the invasive of surrounding open land. rapidly shades out native grasses, dense stand of seedlings in Figure 1 Why invasive? Most Bradfords forbs, shrubs and native tree seed- will grow into a hostile thicket that produce copious crops of small (1/2 lings. This will dramatically reduce will be dangerous place to walk your inch) hard pears. With the onset of the native plant diversity of the site. pet, or for your children to play in. cooler weather, these fruits soften up A site that might contain an attrac- So the invasive nature of Brad- a bit and become very popular with tive, interesting community of native ford pear has the potential to radi- birds. The seeds pass through the grasses, sunflowers, asters and native cally change the natural landscape in birds and get deposited on the sur- legumes is converted to an ecologi- your neighborhood. Diverse native rounding land. These seeds are very cally barren monoculture of Bradford plant communities will be converted viable, and germinate and establish pears. This loss of plant diversity has to a boring thicket of pear trees. The in large numbers. The result can impacts far beyond the plant world. 2 South Carolina Native Plant Society • Spring 2011 loss of native species com- munities, and their complex Name That web of insect herbivores, will create an ecologically Native Plant barren community of little I am a cool-season grass, so I value in the support of am flowering and making seed this breeding populations of spring. Here you can see my flower, songbirds and other wild- and you might say, “That’s not much life. And the pear forest of a flower.” Well, this flower serves me just fine! I am wind-pollinated, so will be a hostile, thorny, I don’t need to worry about attracting dangerous place, fit for insects to help me with passing my neither man nor beast. All pollen around. Both my male and this from a home landscape female flower parts are exposed in the tree that at best will last photo below. My flowers are typical 15-20 years? In my opinion, of the grasses. Notice that the leaf it doesn’t add up. and sheath on my shoot base are very But there are some hairy, almost silky, which may be the beautiful native tree spe- derivation of my Latin species name. cies alternatives that are Look for me on a roadside near you. not invasive, and that are compatible with songbirds Figure 2. Bradford seedlings at the base of a handy bird roosting site across the street from several landscape speci- and other wildlife. These mens. Photo courtesy of the author. include: Various hawthorns, Cra- taegus L. * Serviceberry, Amelanchier Medik. Redbud, Cercis L. Fringetree, Chionanthus L. Red maple, Acer rubrum L. Southern sugar maple, Acer barbatum Michx. *Latin names are hyperlinks to information pages on the Flowering (a spikelet with two open USDA Plants website) florets and two not yet open.) For more information on invasiveness of Brad- ford pears, go to: Plant Invaders of Mid-At- lantic Natural Areas at: http://www.invasive.org/ eastern/midatlantic/pyca. html For information on the links between native plants, native insects and songbirds read: Bringing Nature Home: How Native Plants Sustain Figure 3. Heavy thorns on Bradford pear seedlings. Wildlife in Our Gardens, by Ouch!! Photo courtesy of author. Douglas Tallamy. Basal stem and leaf (blade and sheath) My name is embedded in text somewhere in this newsletter. South Carolina Native Plant Society • Spring 2011 3 Spider Lily, from page 1 stream shoal. Now the only ACE) describing pre-dam shoals on two shoals the Savannah River from Augusta to remaining in the (Georgia) Broad River. (For those the Savannah not familiar with the Savannah River, River are where there are three USACE dams on the the Broad River Savannah River. Discharges from enters the top of Thurmond Dam, about 15 river miles Thurmond Lake above Augusta, heavily impact flow and the Augusta rates through the Augusta Shoals.) Shoals. Histori- What we found: The major dif- cal records indi- ferences between the thriving Stevens cate that there Creek population and populations were at least 15 Figure 2. Stevens Creek site after a rain event. Photo courtesy of in the Augusta Shoals were severe shoals between Judy Gordon. deer herbivory in one Augusta Shoals Augusta and the young seedlings of the lily, marked population, and, just as important, Broad River prior to dam construc- and placed in rock crevices.