Cool-season annual legumes are used in the southeastern USA (central Texas and Oklahoma east to the Atlantic Coast) because of poor persistence of perennial legumes through the hot summers. They are primarily used for overseeding warm-season perennial grasses to extend the grazing season, contribute nitrogen to the pasture system, produce forage with higher nutritive value than gasses, and provide spring weed control through plant competition. Cool-season annual legumes are more soil specific than grasses so several species are used because of soil and climatic differences in the southeastern US. Drought, diseases, temperature extremes, and dependable reseeding are major limitations for expanded use of cool-season annual legumes. The legume breeding project at the Texas A&M University Agricultural Research and Extension Center at Overton is working on the limitations of the following species: arrowleaf clover (Trifolium vesiculosum Savi), virus and fungal diseases; ball clover (Trifolium nigrescens Viv.) uniform morphology and flowering; berseem clover (Trifolium  alexandrinum L.) low cold tolerance and poor reseeding; crimson clover (Trifolium incarnatum L.), early flowering and poor reseeding; rose clover (Trifolium hirtum All.) high winter dormancy; and annual sweetclover (Melilotus alba Medik.) rust diseases, coumarin toxicity, and thick single stems. Apache arrowleaf and Overton R18 rose clover have been released and releases of ball, crimson, and sweetclover will follow in the next 2 to 4 years.