|Johnsongrass was introduced from the Mediterranean to the United States as a forage grass. However, when under frost or moisture stress it becomes toxic to livestock. It reproduces by seed and creeping lateral root systems. It thrives in rich soils and along waterways.
Johnsongrass is a hardy perennial grass. It displays erect stems two to eight feet tall. Spreading roots send large fleshy rhizomes to the sides for wide distribution. Leaf blades are flat, up to one inch wide, with a prominent light midvein. Stems are stout with prominent nodes. Seedheads are reddish to purple.