WITCHGRASS

witchgrass, witch grass, old witchgrass, old witch grass, tumble grass, Panicum capillare

(noun) North American grass with slender brushy panicles; often a weed on cultivated land

Source: WordNet® 3.1

Etymology

Noun

witchgrass (usually uncountable, plural witchgrasses)

Any of several grasses, of the genus Panicum, often found as a weed.

couch grass (a European grass that spreads rapidly, Elymus repens)

Source: Wiktionary