The common name rescuegrass refers to the ability of the grass to provide forage after harsh droughts or severe winters.

Bromus catharticus is a coarse winter annual or biennial grass, growing 0.2–1 m (7.9 in – 3 ft 3.4 in) in height.

The grass lacks auricles and the glabrous ligule is 1–4 mm (0.039–0.157 in) long.

The leaf blades are 4–30 cm (1.6–11.8 in) long and 3–10 mm (0.12–0.39 in) wide and are glabrous or pubescent.

Each flat and pointed spikelet is 20–40 mm (0.79–1.57 in) long and has four to twelve florets.