Old-witch grass

Panicum capillare, the old-witch grass or common witchgrass, is a tufted summer-annual grass in the family Poaceae native to North America and widely naturalized across temperate regions of Eurasia, South America, and Australasia. Plants are erect to ascending, 20-80 cm tall, with stout culms and a fibrous root system. Leaf blades are flat, 4-12 mm wide and 10-30 cm long, light green, and conspicuously clothed in long soft spreading hairs on both surfaces and along the sheath; the ligule is a dense ring of short hairs about 1 mm long. The inflorescence is a very large open diffuse terminal panicle 15-40 cm long and often nearly as broad — frequently more than half the total height of the plant — with delicate strongly branched flexuous branches bearing many small ovate-elliptic spikelets 2-3 mm long at the tips. Each spikelet contains a single floret. At maturity the entire panicle breaks off at the base and tumbles in the wind, scattering seed far from the parent plant in classic tumbleweed fashion. Flowering takes place from midsummer to autumn. Caryopses are tiny, smooth, and shiny. The species inhabits dry sandy or gravelly soils in arable fields, gardens, roadsides, sandbars, and disturbed open ground.