Melilotus officinalis (L.) Lam. (Family: Fabaceae)

Description: White and yellow sweetclover are very similar, sweet-smelling, biennial herbs and members of the pea family (Fabaceae). Second-year plants are bush-like and grow to be 3 to 5 feet tall. The plants’ leaves are made up of 3 oblong leaflets, each 0.5 to 1.5 inches long, with small, sharp teeth. Leaves and stems may be hairless or may have fine, short hairs. Tiny, irregular, white or yellow flowers are present from April to September along spikes up to 6 inches long. Fruits are flattened pods, present from May to October, which contain 1 or 2 seeds each.

Origin: Sweetclovers are native to Eurasia. They were introduced to North America as a forage crop. They are still planted as forage and as a soil enhancer (they are nitrogen-fixing), mainly in the Great Plains and the Midwest. Distribution: Sweetclovers grow well in direct sunlight or partial shade and calcareous or loamy soils. They are most often found in open, disturbed, upland habitats such as abandoned fields, roadsides, prairies, savannas, glades, and dunes.

Problem: Sweetclovers easily invade open areas. They compete with native plants for resources and shade plants that need sun. Fire improves the next year’s germination.

Control: Sweetclover can usually be controlled without the use of herbicides. Plants should be hand-pulled in May or June before flowering and removed from the area.

For more information, see http://www.invasive.org/species/weeds.cfm.

Photo credits:

• Karan A. Rawlins, University of Georgia, Bugwood.org, Image Number: 5404727
• Bonnie Million, National Park Service, Bugwood.org, Image Number: 5405718
• John M. Randall, The Nature Conservancy, Bugwood.org, Image Number: 5392360
• John M. Randall, The Nature Conservancy, Bugwood.org, Image Number: 5392344
• John M. Randall, The Nature Conservancy, Bugwood.org, Image Number: 5392361
• Steve Dewey, Utah State University, Bugwood.org, Image Number: 1459692
• Michael Shephard, USDA Forest Service, Bugwood.org, Image Number: 1196184