An annual, warm-season grass of tropical origin said to have been grown in Egypt since early times, though its value was first recognized in Sudan only in 1909. In that same year it was introduced into the United States as a replacement for johnsongrass, which had become a noxious weed in many southern states. Sudangrass (Sorghum bicolor var. sudanense, also called S. sudanense and S. vulgare var. sudanense) requires warm temperatures for good production, and therefore it is not well adapted to the more northern areas of the United States except as a short-season hay crop. Sudangrass does best on a rich loam, but it has been grown successfully on a broad range of soils. Cold, poorly drained soils are particularly unsuited for sudangrass.