Weeds Identification Gallery

Soft Brome

  • Bromus hordeaceus
  • Grass Family: Poaceae
Updated: 09/2025

Soft brome, also called soft chess, is a widely distributed annual at lower elevation areas in California, especially in open, disturbed areas. Plants are found mostly up to 3300 feet (about 1000 m) and occasionally up to 7000 feet (2100 m). Soft brome inhabits agricultural land and disturbed sites in plant communities. It is able to colonize sites with low soil fertility.

Habitat

Grassland, sagebrush communities, rangeland, fields, open disturbed sites, roadsides, orchards, vineyards, and agronomic crop fields.

Seedling

Seed germination starts in fall.

Young Plant

Young plants grow rapidly during fall with available moisture and slow down through winter. Resuming rapid growth in spring, plants reach maturity in early summer.

Mature Plant

Plants reach 4 inches to more than 2 feet (61 cm) tall and are distinguished by dense, soft hairs on sheaths.

mature plant showing flower heads San Luis Obispo Co.; 4/88 Credit: Jack Kelly Clark, UC IPM
Mature plant. Credit: Jack Kelly Clark, UC IPM

Collar Region

Ligules are membranous. There are no auricles.

closeup of collar showing short, jagged ligule and long, fine hairs on leaf sheath and leaf blade San Luis Obispo Co.; Credit: Jack Kelly Clark, UC IPM
Collar. Credit: Jack Kelly Clark, UC IPM

Flowers

Soft brome blooms from April through July. Compact spikelets form dense flowering heads with needlelike awns about 1/4 to 1/2 of an inch (0.64–1.3 cm) long, usually straight, but sometimes curved outward.

flower head showing short-awned spikelets San Luis Obispo Co.; 4/88 Credit: Jack Kelly Clark, UC IPM
Inflorescence. Credit: Jack Kelly Clark, UC IPM

Reproduction

Soft brome reproduces by seed.

  • Ripgut brome, Bromus diandrus
  • Rescuegrass, Bromus catharticus

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