Flower:

Flowers are in a loose cluster (raceme) at the end of a stem that arises from a leaf axil. Individual flowers are a typical shape for a member of the pea family, slightly elongated, ½ to ¾ inch long. The color ranges from pink to purple to blue. One plant has 1 to several clusters scattered around the plant, with 2 to 9 flowers in a cluster.

Leaves and stem:

Leaves are compound in groups of 4 to 8 pairs, with a tendril at the end of the leaf stem that winds around other plants for support. At the leaf joint is a pair of appendages (stipules) that are up to 1/3 inch long, sharply pointed at both ends, and 3 sharp teeth in the lower half. Leaflets are generally oval and may have rounded, blunt or pointed tips. Each is up to 1½ inch long and about ¼ inch wide, toothless and hairless, becoming smaller towards the end of the leaf stem. The main stem is angled, but otherwise smooth.

Fruit:

Fruit is a pea-shaped pod, about 1 inch long, that turns from green to reddish brown as the fruit ripens. Pods contain an average of 10 seeds.

Notes:

There are several members of the pea family that are climbing vines with purplish flowers. One major distinguishing feature is the stipule at the leaf joint, which is unique for each species. American Vetch plants with rounded leaves might look similar to Crown Vetch when not in bloom, but the leaves of Crown Vetch are more uniform in size, greater in number, and there is no tendril at the end. The flowers are distinctly different between the two.