An Illustrated Guide to ARIZONA WEEDS
The University of Arizona Press
WITCHGRASS, tumble panic, witches hair
WITCHGRASS-Panicum capillare L.
DESCRIPTION-A bushy, conspicuously hairy annual with a shallow root which reproduces only by seeds. The stems are hairy, erect or mostly spreading, and branched from the base, 1/3 to 3 feet high. The leaves are 1/4 to 1/2 inch broad, and are covered (especially the bases) by long, soft or stiff hairs. The mature flowering part is very large and bushy, often half the length of the entire plant, greatly spreading and diffusely branched, with the branches stiff and threadlike. It is brittle when ripe, and often the entire flowering part breaks away and is blown about by the wind as a "tumbleweed." One spikelet occurs at the tip of each little branch. The spikelets are 1/2 to l/8 inch long, with a smooth and shiny yellow or gray grain, which is about 1/16 inch long.
DISTRIBUTION-Witchgrass is a native weed of dryish soil. Common along sandy canyon washes, streams, open ground and pasturelands, it has increased and spread in Arizona with the increase in agriculture. It has become abundant in the irrigated lands, cotton and alfalfa fields, and also occurs in flower beds, gardens, and waste places throughout most of the state; 100 to 8,000 feet elevation; flowering from May at lower elevations, or from July at higher elevations, to October. The grains are frequently found in commercial alfalfa seed and other small seeds.
Copyright (c) 1972 The Arizona Board of Regents