General Description: A coarse-textured perennial with stout unbranched stems and thick aggressive rhizomes. It can grow to 2 m in height and form large stands.
Seedling: The first leaf blade is only 8 times longer than wide and opens parallel to the ground. Leaves are rolled in the bud; auricles are absent, and the ligule is membranous with shallow teeth across the top. Blades are 4 to 18 cm long and 2 to 5 mm wide, smooth on both surfaces and margins, with a prominent midvein near the base of the blade. Sheaths are smooth, rounded to slightly compressed, green or with a maroon tinge. The collar is narrow and whitish. Mature Plant: Leaves are similar to those of seedlings. The ligule (3 to 4 mm) is membranous and may be jagged across the top. Older ligules have a fringe of hairs on the top half, but are membranous at the base. Blades are 15 to 50 cm long by 10 to 30 mm wide, smooth below and mostly smooth above, with some hairs present at the base of the blade near the ligule. The margins are rough, and the blades are flat, with thick prominent white midvein. Sheath is smooth, pale green, reddish brown to maroon, compressed, often with hairy margins. The collar is broad, light green or white, and smooth. Flowers and Fruit: Flowers are present from June to July. The seedhead is a large (15 to 50 cm long), open, coarse, purplish panicle. Spikelets are in pairs. The shorter, wider floret produces a seed and has a twisted awn that is each detached. The seed is 3 to 5 mm long, oval, and dark reddish brown. The other infertile stalked spikelet is longer but narrower and lacks an awn. Distribution: Found through most of the southern United States and West Coast. It is rapidly spreading northward. Crops Affected: Corn, Soybean, Wheat Animal Poisoning: None Similar Species: Shattercane is closely related to johnsongrass and at certain stages of development may be difficult to distinguish. But it is an annual and does not have large rhizomes. Shattercane also has leaf blades much wider than those of johnsongrass. In addition, seeds of shattercane are much larger and more rounded than those of johnsongrass. Fall panicum has similar foliage, particularly with white midvein on the left blade. However, it is an annual that is considerably smaller than johnsongrass and has a hairy ligule that is not membraneous at the base.