This valuable crop (the common "alfalfa" or "lucerne") has been widely grown in Ky. for hay and forage since the 1890s (Gm). It is perennial, but tends to decline after 4-8 years due to varied pests and pathogens. Many colls. mapped here probably are from persistent plantings in old fields, rather than from secondary establishment by seed. The few reports of ssp. falcata (L.) Archang. ("yellow alfalfa") are all from cultivated plants.