Recently added to Minnesota’s Restricted Noxious Weed List, crown vetch (Securigera varia) is difficult to control once it is established. It is native to central and Eastern Europe and the Caucus region of Asia. Crown vetch was widely planted as a groundcover, cover crop, and slope stabilizer, but these uses declined due to the invasive nature of the plant.
Crown vetch is an herbaceous perennial in the legume family. It has a low, groundcover growth habit. The leaves are dark green and pinnately compound with 15-25 pairs of oval-shaped leaflets. The flowers are pink to white and occur in clusters at the leaf axils. The plants bloom from May through August.
Crown vetch spreads by seeds and aggressive rhizomes. The rhizomes grow horizontally up to 10 feet and produce new plants vegetatively. Crown vetch can be introduced to new areas by soil contaminated with root fragments.
Crown vetch invades prairies, woodland edges, streambanks, pastures, rights-of-way, and roadsides. It prefers open and sunny habitats, is tolerant of all different soil types, and is drought tolerant. Crown vetch overtakes and suppresses other vegetation, reducing species diversity and wildlife habitat. Because of its low, creeping growth habit, it can cover and shade out other plants, eventually forming dense monocultures.
Several management strategies may be necessary to keep crown vetch from spreading: