Aster family (Aster family)
Description: This herbaceous perennial wildflower is 1½–3' tall with each stem branching occasionally in the upper half. Because of vegetative offsets, multiple stems usually develop. The pale to medium green stems are strongly winged from the decurrent leaves; they are usually canescent, but some populations of plants can have either glabrous or hairy stems. The alternate leaves are up to 3" long and 1" across; they are pale to medium green, lanceolate to narrowly ovate, smooth along their margins, and canescent to glabrous. The base of each leaf clasps the stem, forming decurrent extensions of the leaf along the stem below.
The upper stems terminate in individual flowerheads about 1" across. Each flowerhead has a globoid center about ½" across that consists of many disk florets that are purple to brown. Surrounding the center of the flowerhead, there are 8-14 ray florets. The petaloid rays of these latter florets are bright yellow, V-shaped (narrow at the base, broad at the tip), and slightly drooping; the tip of each ray is defined by 3 rounded lobes. At the bottom of each flowerhead, there is a single series of floral bracts that are pale green and lanceolate in shape; they become recurved when the flowerheads are in bloom. The blooming period occurs from mid-summer to early fall and lasts about 2 months. The rays fall to the ground, while the disk florets in the globoid center develop into small achenes. Each achene is about 1.0 in length or a little longer and bullet-shaped; there is a crown of awned scales at its apex. The root system is fibrous, forming vegetative offsets.
Cultivation: The preference is full or partial sun, wet to moist conditions, and a slightly acid soil. This wildflower will wilt if it is allowed to dry out. Temporary flooding is tolerated.
Range & Habitat: Purple-Headed Sneezeweed is common in southern Illinois and uncommon in central Illinois, where it is native; in the northern section of the state, where this wildflower is rare, local populations probably derive from escaped cultivated plants (see Distribution Map). Habitats include thinly wooded swamps, soggy riverbottom meadows, wet prairies, moist swales in upland prairies, moist depressions in rocky glades, borders of sinkhole ponds, ditches, pastures, and abandoned fields. This wildflower is found in both high quality and disturbed habitats.
Faunal Associations: The flowerheads offer nectar and pollen as floral rewards to a wide range of insect visitors, including long-tongued bees, short-tongued bees, wasps, flies, butterflies, and skippers. Various insects feed on the leaves, pith of the stems, and other parts of Helenium spp. (Sneezeweeds). These species include the caterpillars of the butterfly Nathalis iole (Dainty Sulfur), the caterpillars of Papaipema impecuniosa (Aster Borer Moth) and Papaipema rigida (Rigid Sunflower Borer Moth), and Smicronyx discoideus (Sneezeweed Weevil). Most of these insects also feed on other herbaceous species in the Aster family. The Greater Prairie Chicken eats the seeds and dried flowerheads of Helenium spp. to a limited extent. Because the foliage is bitter-tasting and toxic, it is avoided by cattle and other mammalian herbivores.
Photographic Location: The wildflower garden of the webmaster in Urbana, Illinois.
Comments: If you can find a sufficiently damp location for it, Purple-Headed Sneezeweed is worth cultivating because of its attractive foliage and flowerheads. Generally, Sneezeweeds (Helenium spp.) can be distinguished from other species in the Aster family by the globoid centers of their flowerheads, their V-shaped and 3-lobed petaloid rays, and their strongly winged stems from the decurrent leaves. Purple-Headed Sneezeweed is easily distinguished from Helenium autumnale (Common Sneezeweed) by the purple to brown globoid centers of its flowerheads; the globoid centers of the latter species are yellow. Another species in Illinois, Helenium amarum (Bitterweed), has very narrow leaves and it prefers drier habitats. Another scientific name of Purple-Headed Sneezeweed is Helenium nudiflorum.