Pale Purple Coneflower (Echinacea pallida) of the Aster or Composite (Asteraceae) family is a heavily pubescent herbaceous perennial with long lanceolate leaves and large, spectacular flowerheads. The genus name is derived from a Greek word for “hedgehog” in reference to the spiny bracts covering the head. The specific epithet is Latin for “pale” in reference to the color of the showy ray florets. In the U.S., the species occurs primarily from western Louisiana and eastern Oklahoma, east and north to Arkansas, Kansas, Missouri, Iowa, and Illinois. Additionally, it is widely scattered in nearby states as well as farther to the east, possibly from introductions. In Arkansas, except for eastern portion of the Mississippi Alluvial Plain, plants grow statewide. Habitat preference is sunny sites with well drained soil: prairies, open woodlands, and rights-of-way.
Plants have a stout vertical rootstock with one or more, near-surface, lateral to ascending “root stubs” that develop leafy crowns. Stubs are encircled by thin scars of dropped leaves. A rootstock may produce a half-dozen or more compact flowering stems. Mature plants, with rootstocks to 2+ feet long, are drought tolerant.
Basal and cauline (stem) leaves are oblong-lanceolate, to 10+ inches long and to ⅜+ inch wide, the basal longer than the cauline, and the cauline gradually shortening distally. They are shiny above and dull below, folded along the midrib, their margins entire (without teeth). Venation is parallel, with a pair of distinct secondary veins on either side of the midvein. Tertiary veins are obscure. The stem leaves are alternate.
Plants have erect rigid flowering stems, 3-4 feet tall, that terminate in a flowerhead. They may bear lateral branches, the longer ones terminating in a flowerhead of reduced size. The upper one-third to one-half of the stems are leafless or bear only a leaf or two. Dead stems and heads persist into the new growth-year.
Conspicuous bristly white pubescence occurs on all surfaces, sparse to moderate along the stems, somewhat denser on the leaves. Pustular based hairs, to 1/16 inch long, are stiff and spreading. Surfaces feel rough.
The inflorescence, in May into June, consists of single terminal flower heads that are to 6¾ inches across with a central dome, the disk, to 1¼ inches wide and ¾ inch tall. Heads comprise closely packed fertile disk florets surrounded by up to 20+ infertile ray florets. Heads are subtended by a saucer-shaped involucre of 3 series of lanceolate bracts with acute tips. Bracts, to ½ inch long and ⅛ wide, are bristly pubescent on their outer surface. Bloom sequence of the disk florets, as with all composites, is centripetal––from the flowerheads’ perimeter toward the center. Flowers have a faint, pleasant scent.
Ray florets have long, drooping, strap-like, spectacular ligules attached to infertile ovaries. Initially erect, they become descending to fully drooped at anthesis. They are pink to pale purple (occasionally white), to 3 inches long and ¼ inch wide, with parallel sides and fringed tips. The outer surface has long, scattered hairs.
Disk florets have tubular corollas about 1/4 inch long, with 5 triangular lobes, 5 stamens (filaments + anthers), and a single pistil (an inferior ovary + style + stigma). Each disk floret is subtended by a stout, hardened, spiny bract longer than the floret, so that the dome of the disk is prickly. The elongate, dark anthers are fused into a ring surrounding the style. With the anther ring exserted above the corolla and bract, the style elongates through the ring moving the pollen from the anthers to above the corolla for ready access by pollinators. With pollen dispersed, anthers wither back into the corolla and the now-exserted style bifurcates and recurves to expose linear stigmatic surfaces. Pollen is white.
In mid-summer, with florets dried, the spiny heads become brown to black and persist on erect hardened stems into the next growing season. Achenes, lacking hairs for wind dispersal, are dispersed by birds, small mammals, and surface water flow. The flattened, shield-shaped achenes are mostly glabrous. Once bracts and achenes have dropped, the conical shape of the receptacle becomes apparent.
In a garden, Pale Purple Coneflower can serve as a tall, airy, accent plant or be intermixed with other plants in a naturalistic setting. Plants are not aggressive self-seeders and remain compact over the years. Once established, plants do well in sunny, rocky areas in various well drained mesic to dry soils. Great for butterflies, bees, and birds. Long lasting as cut flowers; fall stems can last for years in dried arrangements.
Four other species of the genus occur in Arkansas: Yellow Coneflower (Echinacea paradoxa var. paradoxa), Purple Coneflower (Echinacea purpurea), Sanguine Purple Coneflower (Echinacea sanguinea), and Glade Coneflower (Echinacea simulata). Of these, Sanguine Purple Coneflower and Glade Coneflower have flowerheads of similar shape and color as Pale Purple Coneflower. Sanguine Purple Coneflower, as compared to Pale Purple Coneflower, has shorter, wider leaves and stems and its involucral bracts tend to have purplish stalks and tips. Its pollen is yellow (instead of white). Sanguine Purple Coneflower is known in Arkansas only from sandhills in Miller County in the southwestern corner of the state. Visually, Glade Coneflower and Pale Purple Coneflower have the same appearance, except ligules of Glade Coneflower droop less and are usually deeper pink in color and its pollen is bright yellow (instead of white). Glade Coneflower occurs in Arkansas in dolomite glades of the Ozark Highlands.
Article and photographs by ANPS member Sid Vogelpohl
Arkansas Native Plant Society 