© Bruce McNitt/Panoramic Images (Virginia)
Smooth Coneflower
The smooth coneflower, Echinacea laevigata, one of nine species of Echinacea native to North America, is a herbaceous perennial of the Asteraceae, or aster family. It is closely related to the more common purple coneflower, Echinacea purpurea.
A basal rosette of lanceolate leaves emerges from a fleshy rhizome and fibrous roots. The leaves are 4 in. to 6 in. long and 1 in. to 3 in. wide, with three to five prominent veins. The winged leaf stalks are purple tinged. The leaf surface is smooth to slightly rough above and smooth beneath. Smooth stems to 4.5 ft. tall with a few alternate leaves support solitary flower heads. The flower heads contain 13 to 21 pale pink or lavender drooping ray flowers surrounding tubular disk flowers that form a hemisphere or cone. The ray flowers emerge rolled, appearing stringlike, and open gradually. Populations in Virginia show considerable differences in the amount of purple in leaves, petioles, and flowers.
The hemispheric or conical seed heads with their spiny protruding bracts give the genus Echinacea its name, from the Greek echinos, meaning sea urchin.
Habitat
Smooth coneflower grows in open sunny areas where it receives little competition from other plants. It is adapted to well-drained neutral to alkaline soils that are rich in calcium and magnesium. Before the arrival of Europeans, it thrived in oak savanna openings where its growth conditions were maintained by fire or grazing.
Today the plant's most available habitat often happens to be places, such as powerline rights-of-way and roadsides, where it is subject to harm by frequent mowing or use of herbicides.
Distribution
The smooth coneflower occurs in only 10 counties in Virginia, North Carolina, South Carolina, and Georgia. It may once have occurred in Pennsylvania, but, if so, it has been extirpated. Populations in Virginia are found in the Upper Roanoke, Middle Roanoke and Upper Dan watersheds.
Life History
Plants flower from May through July and set seed from July through October. Although the flowers attract bees and butterflies, specific pollinators and seed dispersers have not been identified.
A single rhizome can produce multiple rosettes, which can divide and become viable plants. Researchers in South Carolina have taken advantage of this natural tendency and propagated plants using both rosettes and cuttings from rhizomes.
Conservation
Virginia lists the smooth coneflower as imperiled, the same as its global status, and the U.S. Fish and Wildlife Service considers it endangered. Populations are small and risk decreasing genetic diversity.
Its plight has diverse causes. Most populations have been affected by habitat degradation due to agriculture or development. Mowing of highway rights-of-way threatens populations unless they are consciously protected, and fire suppression has allowed encroachment of competing plants, which the smooth coneflower cannot tolerate.
Landowners can protect smooth coneflower habitat by removing woody plants with periodic, but not frequent, mowing or by prescribed burning. Because the smooth coneflower requires at least partial sun, trees should not be allowed to shade its habitat. Where the plant occurs along roads, the area can be marked to prevent destruction by mowing.
Finally, because the smooth coneflower hybridizes readily, specimens of other Echinacea species, such as purpurea, should not be planted near natural populations of E. laevigata.
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