Aster family (Asteraceae)
Description: This native perennial plant is 1-3' tall and unbranched. The central stem is hairless, except for small tufts of hair at the base of the leaves.The opposite leaves are about 2-4" long. They are usually divided into 3 narrow lobes, but are sometimes linear near the inflorescence. The larger central lobe may also be divided into 1 or 2 small narrow lobes. These leaves are medium to dark green, sessile, and hairless. They are distributed evenly along the stem.
The composite flowers are bright yellow and 1½-2" across. Each composite flower has numerous disk florets, which are surrounded by about 8 ray florets. The outer edges of the ray florets are less ragged in appearance than the ray florets of many other species of coreopsis. The blooming period occurs during early summer, and lasts about 3 weeks. There is no floral scent. The achenes do not have tufts of hairs. The root system is rhizomatous, and can produce dense colonies of this plant that exclude other species. During the fall, the foliage often acquires reddish tints.
Cultivation: The preference is full sun and mesic to dry conditions. This plant isn't fussy about soil characteristics, but will grow readily in soil that is loamy, sandy, gravelly, or full of clay. It is an easy to plant to grow, but may sprawl unless it receives full sun and rather lean treatment. It can spread aggressively. The foliage usually remains in good condition until hard frosts during the fall.
Range & Habitat: Prairie Coreopsis occurs occasionally in most counties of Illinois, but is rare or absent in SE Illinois and some western counties (see Distribution Map). Habitats include mesic to dry black soil prairies, sand prairies, gravelly hill prairies, thickets, open areas of rocky upland forests, Black Oak savannas, limestone glades, and abandoned fields. It is usually found in high quality habitats because the dispersion of the seeds is rather limited.
Faunal Associations: The flowers are visited by many kinds of insects, especially long-tongued bees, short-tongued Halictine bees, and flies. Other insect visitors include wasps, butterflies, skippers, moths, and beetles. These insects usually seek nectar from the flowers, although bees often collect pollen for their larvae and adult beetles eat pollen. The long-tongued bee Melissodes coreopsis (Coreopsis Miner Bee) is an oligolege of Coreopsis spp. The caterpillars of the moths Tornos scolopacinarius (Dimorphic Gray) and Eynchlora acida (Wavy-Lined Emerald) feed on the foliage of this and other coreopsis species. Mammalian herbivores occasionally consume the foliage of Prairie Coreopsis, including rabbits, groundhogs, livestock, and probably deer.
Photographic Location: Photographs were taken at the webmaster's wildflower garden in Urbana, Illinois.
Comments: This plant has the advantage of flowering somewhat earlier during the summer than many other prairie wildflowers. It is more impressive when allowed to form dense colonies. Prairie Coreopsis can be distinguished from many other species of coreopsis by the less ragged appearance of its flowers and the characteristics of its foliage. The narrow, deeply lobed leaves are wider and less thread-like than Coreopsis grandiflora (Large-Flowered Coreopsis) and Coreopsis verticilliata (Whorled Coreopsis), which are not native to Illinois. Also, the leaves are shorter, more deeply lobed, and distributed more evenly along the stem than Coreopsis lanceolata (Lance-Leaved Coreopsis). Prairie Coreopsis is much shorter and blooms earlier than Coreopsis tripteris (Tall Coreopsis).