Vicia americana

American vetch

Fabaceae

The Basics

USDA Plant Database

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Magnoliophyta (flowering plants). Class - Magnoliopsida (dicotyledons). Subclass - Rosidae. Order - Fabales. Family - Fabaceae (pea family). Genus - Vicia L. (vetch) Species -Vicia americana ex Willd.

Ecology: American vetch grows in a wide variety of habitats. It is found in moist to dry areas, swampy woods and borders, mixed forests, and clearings. It is common in moist or sheltered foothill canyons and meadows. American vetch is a nitrogen fixer and has a strong drought tolerance. It may be useful revegetating open or depleted quaking aspen (Populus tremuloides) game rangelands in Utah, including burned over or thinned conifer areas. It is also useful for revegetating coal-mined lands, roadsides, and in critical-site stabilization.

American vetch provides excellent forage for livestock and wildlife. Mule deer, black bear, and grizzly bear browse the leaves and flowers. American vetch also provides forage for game birds and small mammals.

American vetch occurs in all stages of succession. It grows in open sunny sites and invades fire-disturbed areas. It is also shade tolerant. It is found in the understories of quaking aspen communities of the upper Great Lakes region and in Engelmann spruce (Picea engelmannii) communities of the Rocky Mountains. Some common forb associates of American vetch include western yarrow (Achillea millefolium), alpine aster (Aster foliaceus), Virginia strawberry (Fragaria virginiana), wildwhite geranium (Geranium richardsonii), sticky geranium (G. viscosissimum), Canada violet (Viola canadensis), western sagebrush (Artemisia campestris), goldenrod (Solidago spp.), western snowberry (Symphoricarpos occidentalis), and sedges (Carex spp.) (FEIS).

Identification

American vetch is a rhizomatous, single-stemmed ascending or climbing perennial forb up to 75 cm tall. The inflorescence is a raceme with up to 10 deep pinkish-purple to reddish-lavender flowers that are 1.25-3.75 cm long, each producing a pod 2.5-3.75 cm long and containing two to several pealike seeds. The showy flowers, growing on stalks from leaf axils, are unusually large for the genus (UTofA). American vetch has a moderate to deeply branched taproot which reaches a maximum depth of about 100 cm (FEIS).

Threats

American vetch is likely top-killed by fire, but it's rated as moderately resistant to fire. Abundance typically increases after low- to moderate-severity fires. The fibrous roots and rhizomes are 1.5 cm to 5 cm below the soil surface and sprout following light- to moderate-severity fires. American vetch also revegetates burned sites via soil-stored seed. In a study of plant succession in the Gambel oak (Quercus gambelii) brush zone in Utah, American vetch showed a higher average number of plants on burned areas than on unburned areas, even after 9 years. In a Douglas-fir habitat type in Idaho, American vetch cover and frequency on sites burned by low-severity fires were greater than on unburned or severely burned sites (FEIS).

Reproduction

American vetch reproduces from seed and creeping rhizomes. New growth begins in early spring to early summer, varying with environment. It flowers from May to August and the seeds mature about one month after flowering (FEIS).

Species Distribution

American vetch is widely distributed across North America. It occurs from central Alaska east across Canada to southern Ontario, south to southern Virginia, and west across the Great Plains to California, Oregon, and Washington (FEIS).

Citation

CalPhotos University of California, Berkeley. 2021. Vicia americana.

FEIS Fire Effects Information System (FEIS), USDA. 2012. Vicia americana.

USDA Plants Database USDA, NRCS. 2020. The Plants Database. National Plant Data Team, Greensboro, NC 27401 USA.

UTofA Lady Bird Johnson Wildflower center University of Texes at Austin, 2016. The Plants Database. TWC staff, TX 78739 USA.