Bromus diandrus

Bromus diandrus_ripgut brome_JM DiTomaso
Photo: Joseph DiTomaso

Synonyms: B. rigidus, B. rigidus var gussonei, B. gussonei

Common names: ripgut brome; great brome; ripgut grass

Bromus diandrus (ripgut brome) is an annual grass (family Poaceae) found throughout California and other western states. Ripgut brome is one of several European annual grasses that have displaced much of the native grass throughout California. Ripgut brome becomes very dry and flammable during the dry season, increasing wildfire frequency. Increased wildfire frequency leads to conversion of shrubland and woodland to grassland. Ripgut brome is reported to hybridize with two other invasive grasses: downy brome (Bromus tectorum) and red brome (Bromus madritensis). Brome seeds may spread great distances via water and soil movement and by clinging to animals and people.

Cal-IPC Rating: Moderate?

CDFA Rating: None?


Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Weed Management Notes

  • Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

Other Bromus diandrus Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - Distribution map and records of this species in California.
  • CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
  • EDDMapS - Distribution of this species in North America.
  • Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.
  • Additional photos

    Bromus diandrus_growth habit_Ron Vanderhoff_ cropped
    Bromus diandrus (ripgut brome) growth habit. Photo: Ron Vanderhoff
    Bromus diandrus_inflorescence_Ron Vanderhoff_cropped
    Bromus diandrus (ripgut brome) inflorescence. Photo: Ron Vanderhoff
    Bromus diandrus_leaf and sheath_Ron Vanderhoff_cropped
    Bromus diandrus (ripgut brome) leaf and sheath. Photo: Ron Vanderhoff