Hedysarum alpinum is a tall branching member of the pea family (Fabaceae) with many pink flowers, found in rocky situations, meadows and tundra; it is a common plant in the river bars of interior Alaska. This species is a perennial herb arising from a branching caudex and large fleshy taproot, growing 20-35 cm high. Leaves are alternate, pinnately compound with 15-20 leaflets and have obvious lateral veins. Leaflets are ovate to elliptic. Inflorescence is a raceme 3-12 cm long of 10-20 pink flowers. Like all pea flowers, they are bilaterally symmetric. The petals are 2.5-3 cm long. Fruit is a dry loment (constricted peapod) with 2-3 segments. The closely related Hedysarum boreale ssp. mackenziei looks very similar, but lacks visible veins on the underside of leaflets, and has somewhat larger flowers.
Hedysarum alpinum is a deciduous perennial species that flowers mid-summer.
Hedysarum alpinum is monoecious with bisexual flowers. Flowers observed in Fairbanks, Alaska were predominately visited by bumblebees (McGuire 1993). Flowers can self-pollinate, but only between different flowers of the same plant (no auto-deposition) (Kowalczyk 1973). Seeds are likely water and gravity dispersed. Seed scarification has been shown to aid germination in controlled studies (Densmore and Holmes 1987). Plants also spread vegetatively via rhizomes.
Hedysarum alpinum roots, stems and leaves are edible and have been a traditional food source for Alaskan natives raw, cooked, roasted or fried. This species is an important early season food resource for grizzly bears, who dig the roots while the plant is still dormant. This species is used for rehabilitation of mining sites in the Kantishna area of Denali.
Hedysarum alpinum is a widespread amphi-Beringian species. In North America, H. alpinum ranges from Alaska into every Canadian province and southward into Maine, New Hampshire and Vermont, and also occurs in Montana, Wyoming and the Dakotas in the west. This species occurs over much of Alaska except the southeastern panhandle and Aleutians. In Denali, H. alpinum occurs park wide in suitable habitat on both sides of the Alaska Range.
Hedysarum alpinum is a low to moderate elevation species that is seen from 134 m to 1533 m with an average plot elevation of 815 m. This species prefers most south facing aspects. It grows primarily on flat to low angled sites with an average plot slope of 9 degrees.
Hedysarum alpinum is an early successional pioneer species that grows in sandy to rocky soils on gravel bars, lakeshores and other recently disturbed areas. It can also persist in the understory of late successional floodplain forests. It prefers calcareous soils and tolerates seasonal flooding, sediment flooding and ice scouring.