Bromus diandrus, commonly known as Great Brome or Ripgut Brome, is an annual grass species originally native to the Mediterranean region. It has successfully naturalized in other parts of the world with similar climates, such as California and southern Australia. Great Brome typically grows to a height of 1 to 3 feet and features rough leaves and prominent white ligules. It is characterized by its upright form and produces seed heads that are both a distinguishing feature and a mechanism for its spread.

Great Brome is often considered a weed due to its invasive nature in non-native regions, where it can outcompete native vegetation and disrupt local ecosystems. It is not typically cultivated in gardens but may be found in disturbed sites, roadsides, and overgrazed pastures. In its native Mediterranean habitat, it is adapted to dry, open areas with well-drained soils. When grown in gardens or agricultural settings, it requires minimal water once established and thrives in full sun. Due to its potential for invasiveness, it is important to manage its spread by removing plants before they set seed.CC BY-SA 4.0