Plants with rhizomes absent or very short, forming tufts. Flowering stems 80–150 cm long, glabrous, sometimes glaucous. Leaf blades 10–35 cm long, 4–15 mm wide, flat, with a pair of usually prominent auricles at the base, glabrous or less commonly somewhat roughened on the upper surface, green or glaucous. Inflorescences 8–20(–30) cm long, erect or more commonly arched or nodding, with clusters of mostly 2(3) spikelets per node, the axis persistent, not breaking into segments at maturity. Spikelets with 3–5 florets, ascending, disarticulating above the glumes and between the florets. Glumes similar in size and appearance, 15–30 mm long (including the awn), the body 6–13 mm long, 0.8–1.5 mm wide, linear, 3‑ or 5‑nerved, flattened or slightly thickened and hard at the base, straight or slightly bowed out at the base, glabrous or roughened, tapered to a long, roughened awn that is usually bent or curved outward at maturity. Lemmas with the body 8–14 mm long, elliptic‑lanceolate, 5‑ or 7‑nerved toward the tip, hairy or less commonly roughened, the tip with the awn 15–30 mm long, roughened, bent or curved outward at maturity. Paleas mostly 8.5–12.5 mm long, the tip pointed and often divided into 2 narrow teeth. Anthers 2–4 mm long. 2n=28. June–October.

Scattered nearly throughout Missouri, but more common north of the Missouri River (U.S., Canada). Bottomland forests, mesic to dry upland forests, upland prairies, ledges of bluffs, and banks of rivers and streams; also pastures, fallow fields, railroads, roadsides, and open, disturbed areas.

Elymus canadensis is considered highly desirable as forage or hay for livestock. Plants with glabrous or roughened (vs. hairy) lemmas have been called f. glaucifolius (Muhl.) Fernald. A common form in Missouri has slightly larger inflorescences with longer awns and the glumes slightly thickened and bowed‑out at the base. This has been called var. robustus (Scribn. & J.G. Sm.) Mack. & Bush. A less common form with thinner‑textured glumes and somewhat shorter awns has been called var. brachystachys (Scribn. & C.R. Ball) Farw. Neither of these varieties appears to warrant formal taxonomic recognition, based on Missouri specimens.

Two historical specimens from Dent and Oregon Counties appear to represent the hybrid between E. canadensis and E. virginicus (E. ¥maltei Bowden). These are characterized by long, robust inflorescences with usually glaucous lemmas and glumes that are relatively broad and thickened at the base, but not strongly bowed out. The awns are relatively straight.