Leguminosae Medicago sativa L.Source: Magness et al. 1971
Alfalfa is probably native to Asia Minor and the Caucasus Mountain area but has been cultivated since antiquity. It was first established as a crop in the United States around 1850 in California. Its culture did not become widespread until the present century. At present alfalfa is grown for hay on about 20,000,000 acres in the United States, with additional acreage grown for seed and pasture. This includes variegated alfalfas, hybrids between M. sativa L. and M. falcata L., a Siberian species.
Many varieties of alfalfa have been selected for local adaptation, disease resistance and growth characters. These include spreading types, either by underground rhizomes or by adventitious shoots rising from lateral roots.
The alfalfa plant is perennial, new growth rising each year from the crown. Stems reach to 3 feet, and 5 to 25 stems may rise from a single crown. The pinnately trifoliate leaves are arranged altemately on the stems. Alfalfa pasture is excellent for hogs, but cattle on alfalfa pasture are subject to bloat unless carefully adapted to the pasture. When seeded with grasses bloat is less of a problem. Much alfalfa is ground as a meal used in feed mixes. Alfalfa hay is highly palatable and nutritious with very high digestible protein, mineral and vitamin contents.