Vetch

(botany) Any of a group of mostly annual legumes, especially of the genus Vicia, with weak viny stems terminating in tendrils and having compound leaves; some varieties are grown for their edible seed.

Any of a group of plants which are mostly annual and perennial legumes with weak viny stems often terminating in tendrils. There are about 150 species in the temperate zones of four continents. The leaves are compound with many leaflets. Vetches are used mainly for green manure, cover crops, hay, and pasture and silage. The seeds are used as concentrate in animal feeds, and some vetches are used as a vegetable for human consumption. Cool temperatures promote best development. In general, are vetches more tolerant of acidic soil conditions than are most legume crops, but they have a relatively high requirement for phosphorus. Identification of vetches is difficult until pods and seeds develop. See also Leaf; Legume.

By the 1960s, some 35 vetch species and subspecies had been found in the United States. Of these 35 species, 16 are native to the United States.

The vetch complex Vicia villosa is the most widely grown. The subspecies of this complex (V. villosa ssp. villosa), commonly known as hairy vetch, is the most winter-hardy and is mostly adapted to the eastern and southern United States, where it is grown as a winter annual or biannual. A second subspecies of this group is woollypod or smooth vetch (V. villosa ssp. varia). It is less winter-hardy than the hairy vetch type and is adapted to the Pacific Coast states.

The vetch complex V. sativa is the second most important species in use in the United States. Common vetch (V. sativa ssp. sativa) is used throughout the United States. Narrow-leaf or blackpod vetch (V. sativa ssp. nigra) occurs mostly as a weed in waste places in the United States. Underground vetch (V. sativa ssp. amphicarpa) produces pods above and below the ground and is being studied for revegetation on marginal lands of the Far East.

Commonly known as the faba bean, horsebean, or broadbean, V. faba produces coarse, upright plants with large leaves and pods. It is one of only several vetches that are important sources of food for human beings.

Purple vetch (V. bengalensis) possesses poor winter hardiness; however, it is useful in the California rice-growing area, where it is used as a soil-improving crop in rotation with the rice (see illustration). Hungarian vetch (V. pannonica), a more winter-hardy type from Central Europe, is grown in the Pacific Northwest for forage, green manure, and seed. One-flowered vetch (V. articulata) has fine leaves and stems but, lacking winter hardiness, is confined to warm regions. Its flat seeds distinguish it from its nearest look-alike, bard or barn vetch (V. monantha), which is very restricted in adaptation. Bitter vetch (V. ervilia) is an erect vetch without tendrils. Bigflower or large yellow vetch (V. grandiflora), an introduced annual that has naturalized in the southern states, the western seaboard states, and the Great Lakes states, has promise as winter cover and reseeds freely. Tiny vetch (V. hirsuta) is an introduced annual that has naturalized along the southern states bordering the Mississippi River, Texas, the eastern seaboard states, the Great Lakes states, and the Pacific Coast states. Narbonne or French vetch (V. narbonensis), a possible wild relative of V. fava, has been cultivated as a forage crop in the eastern United States and has locally established as a weed in Maryland and the District of Columbia. Bird or purple-white tufted vetch (V. cracca) is a winter-hardy perennial, and its subspecies, cow or bramble vetch (V. cracca ssp. tenuifolia), is considered to be an invasive weed in the eastern United States and parts of Canada. Four-seeded, sparrow, or lentil vetch (V. tetrasperma), also considered an invasive weed, is an introduced annual that has naturalized along and east of the Mississippi River and in the Pacific states.

Purple vetch in flower. (USDA)

Crown vetch, Coronilla varia, is a long-lived, winter-hardy perennial legume, but it is not a true vetch. Spreads by seeds and rhizomes to form a dense, weed-free, erosion-resisting ground cover. Its greatest use is for erosion and weed control on unmowed slopes of highways, industrial developments, and military installations. Its forage value is being studied. See also Cover crops; Soil conservation.