Invasive Plant Species Control
Sweet Clover
(Melilotus alba, Melilotus officinalis)
Native Substitutes
- Round-headed bush clover (Lespedeza capitata)
- Canada milkvetch (Astragalus canadensis)
- Culver's root (Veronicastrum virginicum)
- Grass-leaved goldenrod (Euthamia graminifolia)
Description
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.
Seeds: One or two hard small seeds per flower. Seeds stay viable in the soil for 30 years.
Root: Strong taproot.
Ecological Threat
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.
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 | Basal bark treatment on stems less than 3" | |
| Cutting, before flowers emerge |
Sources
Wisconsin Manual of Control Recommendations for Ecologically Invasive Plants, 1997
Minnesota Department of Natural Resources, Restore Your Shore CD, 2001
