However, decades later when southern ranchers sought a good forage grass for the expanding cattle business, they found large crabgrass perfectly suited because of its affinity for hot, dry conditions and its nutritious qualities as pasture and hay. Immigrants from Poland and central Europe in the late 19th century and early 20th century brought crop and garden seeds, including crabgrass, with them. A form of millet native to central Europe, crabgrass thrived in many soil types, grew and matured rapidly, and produced abundant yields, making it a reliable crop. However, characteristics which once made crabgrass a valued crop now make it a pernicious weed. A large crabgrass plant can produce 700 tillers and 150,000 seeds in temperate areas like the United States and even greater numbers of seeds in tropical climates, where it grows as a perennial and flowers all year.
Large crabgrass is troublesome in temperate and tropical crops.
Its latitudinal range extends from 50 N to 40 S. Because of its ability to adjust to tropical and temperate conditions, it is reported as a weed in 33 crops in 56 countries. It is found among shrubs or ground cover in ornamental planting and along roads and ditches. The plant reproduces by seed, but roots at the nodes to form mats in moist soils. It is a serious weed of lawns, because the stems are usually prostrate and below the mower blade. The rapidly growing seedlings soon crowd out preferred finer-leaved grass species.