Large-flowered Trillium
(Trillium grandiflorum: Liliaceae)
Description: Large-flowered trillium (Trillium grandiflorum) is the largest and showiest of the trilliums. This member of the lily family produces a single, large, three-petaled white flower, which turns pink with age. The flower, which can be from 2-4 inches wide, is produced on an erect stalk with a whorl of three broad leaves at the base. The leaves can be oval to diamond-shaped and are 3-6 inches long (Niering and Olmstead 1979).
Characteristic white, 3-petaled bloom of the large-flowered trillium (NCNatural 2000)
Geographic Range: This species can be found across the Eastern and Central U.S. from Georgia in the South to Arkansas in the West to Minnesota in the North. Large-flowered trillium is also found in Ontario, Quebec, New Hampshire, and western Maine (Niering and Olmstead 1979).
Habitat Requirements: T. grandiflorum is typically found in richly wooded areas and thickets, usually in basic or neutral soils (Niering and Olmstead 1979).
Flowering: The large-flowered trillium typically blooms from April to May with exact bloom time depending on geographic location (Hipps 1996). Blooming begins in late April in the preserve.
Large-flowered trilliums in full bloom in
Banner Elk, NC
(Avery/Banner Elk Chamber of Commerce)
Distribution on the Preserve: Several small patches of large-flowered trillium ranging in size from a few isolated individuals to rather dense patches of 50 or more individuals can be found scattered throughout the preserve. Medium-sized patches (50-100 individuals) have been noted in both the northeastern corner of the preserve about 50 meters south of the shore of Kelley Lake and along the southern Amway property boundary. These patches typically range in size from a 10 to 100 square meters. Patch densities can range from a few individuals per square meter to upwards of 20 or 25 per square meter in the densest patches. The largest patch observed within the preserve is located in the southeastern corner. This dense patch, which spans over a thousand square meters, is by far the largest trillium population within the preserve. Trillium can also be found all along the western boundary where the preserve meets with the local housing development. Most trilliums within the preserve tend to be found in low-lying areas though some were found on hillsides as well, especially along the western edge of the property.
Status on the Preserve: Although the large-flowered trillium population within the preserve seems to be doing very well (the observed population size is considerably greater than anyone had anticipated), these flowers may face increasing adversity in the future if the deer population within the area increases. Deer feast on the leaves of the plant and can decimate local populations. As the area becomes more fragmented with the onset of heightened development, it is likely that the deer population, which thrives in such fragmented conditions, will also increase. Such an increase is likely the greatest threat facing the large-flowered trillium population within the preserve (Augustine and Frelich 1998). However, T. grandiflorum does not seem to be adversely affected by development itself as trillium patches can be found all along the edge of the property where it meets up with the housing development and even in the yard of some of the residences.
On another note, the large-flowered trillium population does not seem to be hampered by the expanding Vinca minor population within the preserve. This invasive ground cover species, which has been implicated in reducing seedling survival, seems to have no ill effect on T. grandiflorum. In fact, trillium can be found scattered throughout many of the densest V. minor patches in the preserve.Literature Cited:
Augustine, D. J. and L. E. Frelich. 1998. Effects of white-tailed
deer on populations of an understory forb in fragmented deciduous
forests. Conservation Biology. 12(5): 995-1004.
Avery/Banner Elk Chamber of Commerce. Large-flowered trillium. Welcome to Avery County. 1 May 2001. http://banner-elk.com/trillium.html.
Hipps, C. B. 1996. Treasured trilliums. Horticulture. 74: 40-43.
Niering, W. A. and N. C. Olmstead. 1979. The Audubon Society Field Guide to North American Wildflowers. Alfred A. Knopf, Inc., New York.
NCNatural. 3 Oct 2000. Large-flowered trillium. Wildflowers and Plants of North Carolina. 1 May 2001. http://NCNatural.com/wildflwr/lgfltril.html.
Contributors: Colleen Iversen, Adrienne Hull, Sandra Bos