Hierochloe alpina is a rhizomatous perennial grass that appears tufted, and can be abundant in the alpine zone in Denali, particularly in heath tundra and along gravelly ridgetops. Basal leaves are narrow and involute with purplish sheaths. Culm leaves are shorter and wider with a 1 mm long fringed ligule. Culms are 10-30 cm tall and topped with a contracted panicle of flowers. Spikelets are 3-flowered with a perfect apical floret and lower florets only staminate. This species is separated from other species of Hierochloe by the characteristic long, geniculate and twisted awn in the second staminate floret. The sweet smell is characteristic of the genus, and the stem has a pleasant, vaguely vanilla taste.
Hierchloe alpina is a perennial species that is often the first grass to flower in the growing season.
Hierchloe alpina is monoecious with bisexual florets. Flowers are wind pollinated, but can also produce seeds asexually through apomixis. Seeds are wind and gravity dispersed.
Hierochloe alpina is a circumpolar species with an arctic-alpine distribution. In North America, this species ranges from Alaska east across Canada to Greenland, and south to New England and Montana. It is common statewide in mountainous regions of Alaska, except absent in the southern Aleutians and much of the southeastern panhandle. In Denali, H. alpina is common in the mountains on both sides of the Alaska Range crest.
Hierchloe alpina is an alpine plant that occurs from 274 m to 1742 m, with an average plot elevation of 1067 m. It slightly prefers east and west facing slopes. It is commonly found on moderate to steep angled sites with an average plot slope of 17 degrees.