Hairy vetch is a branching, spreading annual that forms a dense ground cover. Flowers in 4-inch-long racemes on long peduncles arising from leaf axils, with 10–30 flowers of the pea type all turned to one side of stalk, in varying colors: rich lavender, purple, violet, or white. Blooms April–October. Leaves alternate, compound, ending in a tendril, with 5–10 pairs of narrowly oblong leaflets to ¾ inch long, with a point at the tip; typically hairy, though some varieties are smooth. Fruit a small pod about 1 inch long.
Similar species: There are 10 species of Vicia recorded for Missouri; about half are native, the rest introduced. Wood vetch, or pale vetch (V. caroliniana), trails or climbs, is smooth and hairless, and has white or whitish lavender flowers, with the keel petal tipped with blue or lilac. It blooms April–June and is found in rocky areas with acidic soils in the Ozarks.