: Melilotus arvensis, Melilotus leucanthus, Melilotus lutea, Melilotus officinalis (L.) Lam. var. micranthus
: White sweetclover
: This plant is capable of nitrogen fixation.
: Herbaceous annual or biennial that can grow up to 1 m (3 ft) tall; deep taproot; extensive lateral roots.
: Compound, alternate, clover leaves with three finely toothed leaflets.
: Upright; many-branched; often hollow; leafy stems that may be somewhat spreading near the base giving the plant a bushy appearance.
: Numerous, yellow in color, pea-like, fragrant, crowded onto elongated stems; bloom May through September.
Fruit and seeds
: Seed pod, tiny, wrinkled, contains 1-2 small seeds that may remain viable for up to thirty years, seed germination stimulated by burning.
: Native to Eurasia. Found in open, disturbed sites such as roadsides and old fields; invades prairies, savannas and dunes; shade intolerant; tolerates nutrient poor soils.
: By prolific seed production; up to 350,000 seeds per plant.
: Resembles non-native white sweet clover (Melilotus alba
), which has white rather than yellow flowers; seedlings may also resemble alfalfa (Medicago spp.
), which has hairs (pubescent) on the leaf underside.
Monitoring and rapid response
: Monitor open, sunny sites; sweet yellow clover is most easily identified in June and July, while in bloom. For small infestations, pull first year plants in fall, after the root-crown buds have developed; pull second year plants before flowering. Flowering plants should be removed and disposed of so that seed does not develop. Poorly planned prescribed fire will increase infestations; multiple hot burns needed, timing critical, dependent on population age structure. A single burn may also be combined with herbicide application.
: The Michigan Natural Features Inventory
(MNFI) has partnered with MISIN to provide the information in this fact sheet. Species images and/or information were used with permission from "A Field Identification Guide to Invasive Plants in Michigan's Natural Communities
" and "A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan