JOHNSONGRASS, Sorghum holepense (L.) Pers. 1, stout stem base, roots, and a young rhizome; 2, panicle; 3, group of spikelets; 4, section of stem showing base of leaf; 5, seed. Perennial, reproducing by large rhizomes and seeds. Root system freely branching, fibrous. Rhizomes stout, creeping, with purple spots, usually with scales at the nodes. Stems erect, stout, from 1-1/2 to 6 feet (0.45 to 1.8 m) or more tall. Leaves alternate, simple, smooth, 6 to 20 inches (15 to 50 cm) long, about 1/2 to 1-1/2 inches (1.3 to 3.8 cm) wide. Panicles large, purplish, hairy. Seed nearly 1/8 inch (3 mm) long, oval, reddish-brown, marked with fine lines on surface, bearing a conspicuous awn easily broken off. Found especially on rich soil. Troublesome in corn and soybeans on overflow bottoms. Difficult to control or eradicate. Listed as noxious weed in states where found.