Perennial tussock grass, slow to germinate, short stem shoots and few leaves. The stiff, wiry culms are 60 cm tall, main flowering period June to July. Found on permanent pastures on poorer soils and mountainous areas where perennial ryegrass tends not to thrive. On well managed grazing land it is suppressed by other grass species. After late flowering the mature grass readily sheds its seed. This ensures its spread. The value of crested dog’s tail has been overestimated in the past. With a score of 6, the feed value is relatively good. However, this applies only to the young stage of growth. Grazing animals are not keen on the stiff, wire-like culms with few leaves which subsequently develop. Crested dog's tail is of little or no importance.
| Leaf | Emerging leaf folded, leaf sheath closed, hairless, leaf blade short with pointed tip, forming a channel, pronounced ribbing, glabrous, bright green. Ligule short and rough, with raised lobes. Auricles absent. |
| Culm | Culm mostly stiffly erect up to approx. 60 cm tall, almost wiry, branched, with few leaves. |
| Inflorescence | Secund, clustered false spikes. Spike spindle wavy (comb-like). Glumes divided, lemma has short awl-shaped tip. Under each normal spikelet is a sterile spikelet. Complete inflorescence approx. 10 cm long. |
| Fruit | 3–4 mm long grain. Lemma reddish yellow, curved at base and covered in white bristles, tipped with awn. Palea yellowish brown in deep furrow. Pedicel short and flange-like. TSW approx. 0.5 g. |