Polygonum alpinum is a tall perennial herb in the buckwheat family (Polygonaceae) with open panicles of white to cream-colored flowers. This species occurs in spruce forests, burned areas and disturbed sites in the boreal zone. Plants grow up to 2m tall from a thick woody root. Leaves are all attached to the stem, ovate to lanceolate with an acute tip and crisped margins, 5-20 cm long. The hollow stem is simple or branching. Flowers are arranged in terminal or axillary panicles, loosely ascending. Flowers are perfect, small, numerous, the small tepals greenish or white. Fruits are achenes. This plant is readily recognizable by its height, many reduced white flowers and long, lanceolate leaves.
Polygonum alpinum is perennial and deciduous. It flowers mid-summer.
Polygonum alpinum is monoecious with bisexual flowers. Pollination and dispersal biology of this species have not been studied. Seeds are likely gravity, water and wind dispersed.
All parts of Polygonum alaskanum are edible either cooked or raw, though shouldn't be consumed in large quantities. Raw roots and stem bases were traditionally used by the Dena'ina to treat coughs and colds (Kari 1985).
Polygonum alpinum is an amphi-Beringian endemic species, occurring only in Alaska, Yukon and the Northwest Territory in North America, and Chukotka in Eurasia. In Alaska, this species ranges from the interior west to the Bering Sea and north to the south side of the Brooks Range. In Denali, this species is most common north of the Alaska Range in the northeastern quadrant of the park, but occasionally occurs south of the range as well.
Polygonum alaskanum is primarily a low elevation species and is found at elevations from 174 m to 1037 m with an average plot elevation of 530 m. It does not show a strong preference for site aspect. It is more commonly found on moderately steep sites, with an average plot slope of 13 degrees.