White and yellow sweet clover (Melilotus alba, Melilotus officinalis)
 Native Substitutes:
 Control Methods  
Mechanical
Chemical
Biological
Prescribed burning, a hot complete first year burn followed by a hot second year burn, (repeat after two years) Spray emergent seedlings with 2,4-D amine or mecamine after a fall burn, or after a spring burn before native vegetation emerges None

 

Hand pulling, effective on small infestations        
Cutting, before flowers emerge        
 
Appearance: Biennial forbs, they are very similar. Yellow sweet clover is usually smaller and blooms earlier. First year plants do not bloom. Second year plants grow 3-5' high and are bush-like. Sweet clovers are very fragrant. Leaves: Alternate, divided into three finely toothed leaflets, middle leaflet is stalked. Flower: Crowded densely at the top four inches along a central stem, each flower is attached by a minute stalk; bloom June through August on second year plants. Seed: One or two hard small seeds per flower. Seeds stay viable in the soil for 30 years. Root: Strong taproot.
Sweet clover invades and degrades native grasslands by overtopping and shading native sun-loving plants, thereby reducing diversity. It grows abundantly on disturbed lands, roadsides, abandoned fields. It responds favorably to prescribed burns by scarifying seeds that stimulates germination. First year plants are hard to detect. Native to Europe, it was brought to the U.S. in the late 1600s as a forage crop and soil enhancer, predominately in the Great Plains and Upper Midwest.
Wisconsin Manual of Control Recommendations for Ecologically Invasive Plants, 1997