Synonyms: Melilotus arvensis, Melilotus leucanthus, Melilotus lutea, Melilotus officinalis (L.) Lam. var. micranthus

Common Names: White sweetclover

Description: This plant is capable of nitrogen fixation.

Habit: Herbaceous annual or biennial that can grow up to 1 m (3 ft) tall; deep taproot; extensive lateral roots.

Leaves: Compound, alternate, clover leaves with three finely toothed leaflets.

Stems: Upright; many-branched; often hollow; leafy stems that may be somewhat spreading near the base giving the plant a bushy appearance.

Flowers: 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.

Habitat: 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.

Reproduction: By prolific seed production; up to 350,000 seeds per plant.

Similar species: 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.

Credits: 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.

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