Scientific Name: Medicago lupulina L.
Black medic is normally a summer annual, but can act as a perennial in some conditions. It has a taproot, and spreads low to the ground, but it does not root from nodes on the stems. Black medic is more active on soils low in nitrogen fertility. The leaf is similar to clover and other legumes, having three leaflets. Black medic's center leaflet is on a separate petiole. The flower of black medic is a compressed cluster of bright yellow flowers in the shape of a globular spike on short branches. The seed pod will turn black at maturity. Black medic produces viable seed under normal mowing conditions. Black medic is found throughout the continental United States.
Good turf management practices, including a balanced nitrogen/phosphorus fertilization program, will encourage a dense stand of turf and make it difficult for black medic to persist. A nitrogen/phosphorus ratio of 2:1 is recommended where black medic has become established. Soil testing can confirm low phosphorus levels.
If cultural recommendations are insufficient for a previously infested area, apply a selective herbicide to actively growing black medic during the seedling to flower growth stage.
Weed Photos: Courtesy of Dr. Lambert McCartey. Clemson University. Clemson, SC.