Culms (24)50-150 cm; uppermost nodes usually towards the middle of the culm. Uppermost sheaths shorter than the blades; blades 4-36 cm long, 2.4-15 mm wide. Panicles (4)10-35(44) cm long, 0.7-10(14+) cm wide; longest branches (1.4)3-13 cm, with (5)50-140 spikelets per branch; secondary branches usually spreading. Spikelets 3-5.2 mm. Glumes unequal; lower glumes 2.3-3.6 mm, 1(-2)-veined; upper glumes 3-4.8 mm, shorter than, as long as, or longer than the lemmas, 3-veined; lemmas 2.4-4.8 mm; anthers 1.3-3.5 mm. 2n = 28, 56.

Arctagrostis latifolia subsp. arundinacea is the predominant subspecies from Alaska east to the western Northwest Territories, northern British Columbia, and Alberta. Cultivars for hay and revegetation mixes have been developed.