Scientific Name
Panicum capillare L.
Common Name(s)
Witchgrass, old witchgrass
Tribe / Family Name
Paniceae
Flowering Period
June to September
Symbol
PACA6
Description
Witchgrass is a native warm-season annual bunchgrass that reproduces by seed. Culms range from 15–130 cm in height. Its inflorescence is a diffuse panicle that is 13–50 cm long, 7–24 cm wide, densely flowered, usually more than half as long as the entire plant, included in the uppermost sheaths, and breaking away at maturity. Spikelets are up to 4 mm long, elliptic, glabrous, acuminate, usually red-purple, and 2-flowered; disarticulation below the glumes. Glumes are unequal (lower glumes usually 1–1.7 mm long, broadly ovate, acuminate, half as long as the spikelet, 1- to 3-nerved; upper glumes usually 2–2.8 mm long, lanceolate, acuminate, midveins scabridulous, 7-nerved). Sterile lemmas are similar to the upper glumes (both exceeding and enclosing the fertile florets). Fertile florets are up to 2 mm long, broadly oblanceolate, obtuse, smooth and shiny, and stramineous or nigrescent. Awns are absent. Sheaths are open and papillose-pilose. Auricles are absent. Ligules are a fringe of hairs up to 1.5 mm long. Blades are 5–40 cm long, up to 18 mm wide, flat or folded, linear, spreading, scabrous, sparsely papillose-pilose, and sometimes only ciliate and more or less glabrous.
General Info
Witchgrass is a common weed found along roadsides, railroad tracks, sidewalks, ditches, in waste places, cultivated fields, pastures, lawns, and other disturbed areas, as well as rock crevices, springs, edges of alkali flats, foothills, plains, and montane sites.
Similar Species
Witchgrass is quite distinctive in appearance. Remember to look for its open diffuse panicle inflorescence and distinctly hairy stems, leaves, and ligules when comparing it to other grasses.
Picture of growth habit.
Close-up picture of diffuse panicle inflorescence.
Close-up picture of spikelet.
Close-up picture of ciliate membrane.
Illustration of witchgrass. USDA-NRCS PLANTS Database / Hitchcock, A.S. (rev. A. Chase). 1950. <i>Manual of the grasses of the United States</i>. USDA Miscellaneous Publication No. 200. Washington, DC.