(Panicum virgatum) Switchgrass is one of the dominant species of the tallgrass prairie, but also grows along roadsides where moisture is present. The rich, yellow-colored clumps last throughout the winter. It is a grass averaging 3 to 5 feet tall. The stem is round and can have a red to straw colored tint. The seed head is an open, spreading panicle. Switchgrass is climatically adapted throughout most of the United States when planted on suitable moderately deep and poorly drained sandy soils. Switchgrass occurs naturally on prairies, shores, riverbanks, high brackish marshes, and along maritime forest environments.