Origin:
Native to Eurasia, and now widespread in the western United States.
Biology:
An annual or short-lived perennial that reproduces by seed. It was introduced as a forage crop in range pasture, but it also is a problem weed in cultivated crops, turf, and landscape. Its spiny seed balls are a major health problem for long-haired pets or livestock, such as sheep.
Identification:
Very similar to Black Medic, but differs by the presence of the spiny seed pods and its more trailing habit. Mature plants trail along the ground, with the tips sometimes ascending or growing up into landscape foliage. Stems may grow to 2 feet in length and are 4-sided and weak. Stems branch out from the base of the plant, and a strong taproot is present. Leaves are divided into 3 round or heart-shaped leaflets, and there is a long, pink to violet petiole. The central leaflet is on a short petiole. Flowers are bright yellow and small, but are in clusters of only 2 or 3 flowers, also differing from Black Medics cluster of numerous flowers. The seed pods are coiled in a tight, ball-like spiral and there are rows of curved spines along the edges of the spirals.
Characteristicts Important to Control:
Seed pods are easily transported by clothing or animal hair, and control should be done prior to seed production. Plants survive easily in dry soils.
