Vetches is a general term referring to many plants belonging to the legume or bean family.
Hairy vetch, a true Vetch in the Vicia genus, is often sown in the fall and plowed under the following spring. The plant is an annual and will die out. Crown vetch, is not a true vetch, though it is a legume. It was or is commonly used by transportation departments to control erosion on banks and interchanges. Crown vetch is drought and cold hardy, disease resistant and seems to grow on the worst possible soils.