Upright annual or biennial that grows 1.5 – 7 feet tall. Has serrated leaflet edges with three leaflets per leaf. Has white or yellow flowers and as extensive taproot. The white-flowered sweetclover (M. alba) is talker, coarser-stemmed, and has coarser leaves than the yellow-flowered type (M. officinalis). Yellow sweetclover is more drought tolerant, more vigorous as a seedling, flowers earlier, and has spreading growth.
Sweetclovers: Managing Cover Crops Profitably (SARE Handbook Series Book 9) by Andy Clark (2007, 3rd ed.)