Hordeum murinum aka Wall Barley

Hordeum murinum is a grass in the Poaceae family. Common names include mouse barley and wall barley. Its native range spans Macaronesia, Europe, and the Mediterranean region. It extends east to Central Asia and the western Himalaya. The RHS lists it as native to Britain and Ireland. It also grows widely as an introduced plant elsewhere.

Mouse barley grows fast and usually lives for one year. Kew also records a two-year life cycle. Plants reach about 2 feet (0.6 metres) tall. Their spread reaches about 1 foot (0.3 metres). Fibrous roots help hold bare soil during early growth. Dense, bristly seed heads give this grass its barley-like look. Young heads are green and fairly soft. They turn pale and stiff as they dry. Ripe heads break into pieces that carry sharp, barbed awns.

This grass grows on disturbed ground and in dry grassland. It occurs in fields, gardens, ditches, roadsides, and pavement cracks. For cultivation, it needs full sun and well-drained soil. It accepts sandy, loamy, and clay soils. It also grows across a broad range of soil pH. Dry or moist soil suits it. PFAF lists USDA hardiness zones 5–10. Wind carries pollen between flowers, which contain male and female organs. Fresh seed sprouts readily after autumn rain. Shallow sowing on bare soil is enough for propagation.

Its main landscape role is quick cover on disturbed soil. Young leaves provide forage before seed heads form. Small birds and rodents eat some of the grain. Yet mature awns pose a hazard to grazing mammals. Seed pieces cling to animals, clothes, and machinery. This helps the grass spread far from its starting point. It can become a weed in gardens and fields. It spreads by seed rather than by rhizomes. Stopping seed production offers the main means of long-term control.

The grains are edible once fully freed from awns and hulls. They can be toasted, boiled, or ground into flour. Small grains and tough hulls make preparation slow and difficult. Brittle heads and sharp awns add to the handling problem. This limits its value as a food crop. PFAF records traditional use for bladder and urinary complaints. Such use does not establish that it works as medicine. The supplied safety evidence concerns sharp awns, not confirmed chemical toxicity.