Redtop is a naturalized perennial grass often used for erosion control as it can form dense tufts. It has a rhizomatous root system, but does not send out stolons.

The stems are usually erect, from 4 to 48 inches high but are sometimes bent at he base such that lower stem nodes can take root.

Leaves are narrow, flat, about 3/8 inch wide and short, up to 4 inches long, sparse on the culm, more clustered at the base. Ligules are longer than wide, with the back side usually rough but sometimes smooth. The ligule tops are rounded to truncate.

The inflorescence is pyramidal in shape, less than 1/2 the length of the stem, branches spreading, slightly rough, with the spikelets found on the outer half of the branch. The array is reddish in color and can be up to 10 inches long. It matures early. The spikelets are narrowly ovate to lanceolate, green and usually strongly tinged with purple. The glumes are sub-equal, lemmas are 3 to 5 veined but not always conspicuous, usually without awns. Anthers number 3.

Habitat: Redtop is found in much of the Great Plains and it can tolerate wet or dry conditions but is generally found in areas where there is moisture or recent moisture such as after flooding.

Names: The genus Agrostis, is a Greek word meaning a forage grass, from the Greek agros meaning "a field". The species, gigantea, means unusually tall or large, referring to the large flowering panicle being almost half the plant height. The author name for the plant classification - ‘Roth’ is for Albrecht Wilhelm Roth (1757-1834) German botanist who published his research and was later associated with the University of Jena Botanical Institute. One of his best known works is the multi-volume Tentamen florae germanicae, 1788–1800, which is still in print.

Comparisons: A confusing species is A. stolonifera, Spreading Bentgrass, which has a somewhat smaller panicle and the root system forms stolons that are either on the surface or just under, which root at the nodes, forming colonies. This is also an introduced species.