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Statewide IPM Program, University of California

Ripgut brome  (Bromus diandrus)

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Life stages of Ripgut brome top left picture top right picture bottom picture

Ripgut brome is a cool season annual grass. It is one of the many European annual grass species that have displaced a large portion of the native grassland vegetation throughout California. Although found throughout California up to an elevation of 6600 feet (about 2000 m), it is most abundant in the central and southern parts of the state. Ripgut brome inhabits natural plant communities, open disturbed sites, and agricultural land. Brome can become established over a wide range of soil moistures. A plant residue mulch favors its buildup. It is highly flammable when dry.


Open disturbed sites, roadsides, fields, rangelands, orchards, agronomic crops fields, forestry sites, and many natural plant communities.


A tubular sheath distinguishes ripgut brome seedlings from most other grass seedlings. Soft hairs cover the blades and sheaths. Wild oat, which is similar, can be distinguished from ripgut brome by gently digging up the seedling and checking the base of the stem. Ripgut brome generally does not have a seed remnant at the stem’s base, but wild oat characteristically has a seed remnant that sticks to the base for a long time after germination and during growth.


The open branching flower head resemble that of oats. Large spikelets with needlelike awns, 1 to 2 inches (2.5–5 cm) long, distinguishes ripgut brome from the much shorter awns of soft brome. The individual flowers have tiny, rough teeth that can injure livestock and pets.


Ripgut brome reproduces by seed.

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