Crown vetch is a perennial legume of the pea family (Fabaceae) that has creeping stems which form dense mounds of vegetation. Each of the compound leaves bears fifteen to twenty-five leaflets. Pea-like pink and white flowers at the end of extended stalks are produced in early summer and develop into narrow, leathery seed pods.
As a legume, crown vetch draws nitrogen from the air, trapping it in the roots, and thus improves soil fertility. However, crown vetch spreads aggressively by the growth of rhizomes and it seeds.
Crown-vetch has been introduced around the US for erosion control since around 1950. While many pea-species provide great fodder for domestic animals, this species is toxic. When consumed in significant proportions it will cause slow growth, paralysis, or even death.