Learn about Rejuvra herbicide Stewardship

Invasive annual grass species such as cheatgrass (Bromus tectorum), medusahead (Taeniatherum caput-medusae), ventenata (Ventenata dubia) and red brome (Bromus rubens) are changing western rangeland and natural areas in a cycle that favors their spread at the expense of desirable vegetation.

They compete with desirable grasses, forbs and shrubs by germinating in late-summer and winter, continuing root development over winter, starting rapid above ground growth in late-winter and stealing moisture and nutrients before desirable perennials start to grow in spring. The invasive annual grasses out-compete the desirable perennial plants and significantly reduce their growth.

// Every year after the annual grasses mature and produce seed, they turn brown and die in late spring into summer. The new seed production is added to the soil seed bank and the dry foliage is added to the thatch layer.

// The thatch layer creates a continuous bed of flammable fine fuel that increases wildfire frequency. Desirable perennial species can be killed or never have a chance to fully recover because of the increased fire frequency. In addition, the wildfires are a threat to humans, wildlife, property and infrastructure. Ranchers are particularly vulnerable because they lose standing forage, livestock, fences, structures and access to grazing lands.

// Invasive annual grasses have minimal forage value or are only optimal for grazing over a very short window. The awns are irritating resulting in livestock avoiding areas with even relatively low levels of annual grass invasion. The invasive annual grasses repeatedly steal moisture and nutrients that would otherwise be used by desirable forage species. The result is reduced forage quantity and quality for livestock and wildlife.

// Wildlife species such as the sage grouse and desert tortoise are at risk because of the dramatic increase in invasive annual grass dominated rangelands and natural areas.