Family: Poaceae

Bromus catharticus, commonly known as rescue grass, is a fast-growing annual or short-lived perennial grass native to South America. It was intentionally introduced to many regions, including Hawaii and the mainland United States, as a valuable forage and pasture grass. It is easily identified by its tall, loosely-bunched growth, bright green blades, and distinctive, large, nodding seed heads. True to its name, it is often used for quick “rescue” forage for livestock, for erosion control, and as a cover crop, providing rapid ground cover and fodder in agricultural settings.

Despite its agricultural benefits, rescue grass poses several ecological risks, particularly in areas outside its native range. It is a highly opportunistic species that readily invades disturbed sites, roadsides, and open natural areas. Its rapid growth and prolific seed production allow it to outcompete and displace native grasses and plants, reducing biodiversity. Furthermore, in places like Hawaii, it can alter fire cycles and soil chemistry. While not as aggressively invasive as some plants, it is still considered a threat to native ecosystems and can be difficult to manage once established, requiring careful consideration before planting in or near sensitive natural areas.

High Risk Traits:

• Elevation range exceeds 2000 m, demonstrating environmental versatility
  
• ‡Grows in tropical climates
  
• ‡Naturalized on main Hawaiian Islands & widely naturalized elsewhere
  
• ‡Environmental weed in Australia
  
• ‡Other Bromus species are invasive
  
• ‡Contains toxic levels of nitrates (may be toxic to livestock if consumed at high levels)
  
• ‡Shade tolerant
  
• ‡Tolerates many soil types
  
• ‡Able to form dense swards
  
• ‡Reproduces by seed
  
• ‡Cleistogamous (capable of automatic self-pollination) in certain conditions
  
• ‡Able to reach maturity in 1 growing season
  
• ‡Seeds dispersed by a variety of vectors (attached to machinery, clothing, animals, by wind, water & as a contaminant
  
• ‡Prolific seed production under certain conditions
  
• ‡Seeds can form a persistent seed bank (4-5 years)
  
• ‡Tolerates mowing & grazing

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• ‡Provides fodder for livestock (palatable despite reports of potential toxicity)
  
• ‡Not reported to spread vegetatively
  
• ‡Herbicides may provide effective control