Poaceae (Grass Family)
Group: Monocot (Grass)
Weak perennial grass from relatively short, thick, scaly underground runners, native of South America. The species often looks somewhat like corn seedlings when small. It can be found in cultivated fields, roadsides, and ditches. Columbus grass is an introgressive hybrid between Johnsongrass (Sorghum halepense) and grain sorghum (Sorghum bicolor).
Seedling leaves are rolled in a bud, smooth, with a prominent midrib. Ligule is membranous and toothed. Leaf sheath is smooth.
Leaf blade of mature plants are flat, sandpapery, 1/2 to 1-1/2 inches wide, and 18 to 32 inches long, lack longer hairs except occasionally at the base on the upper leaf surface. Leaf sheaths are smooth. Ligule is a prominent membrane.
Stem is stout and up to 14 feet tall.
Flower or seed head is an open panicle. Seed heads are 6 to 24 inches long with wide spreading branches. Flowers are born in pairs, one with a stalk and one without. Flowers and seeds are 3/8 to 1/4-inch long and seeds are smooth.
Roots are fibrous from rhizomes.
Propagation is by seed or underground runners. The thick underground runner makes this weed difficult to control.