Cheatgrass (Downy Brome)
Bromus tectorum · Cool-season, Winter Annual, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Bromeae
Grass Category
Invasive/Weed Grass, Forage (early spring only)
Variety / Cultivar
Generic wild species (No common turf cultivar)
Hardiness Zones
USDA Zones 3-11; extremely cold hardy as a winter annual and heat tolerant due to its rapid life cycle ending before peak summer heat.
About This Grass
An annual grass reaching 2-24 inches depending on moisture. It is characterized by its light green, hairy leaves and a drooping, panicle seed head that turns reddish-purple-to-tan as it matures and dries.
Blade Characteristics
Blades are 2-4mm wide, flat, and densely covered with soft hairs (pubescent). Tips are pointed. Vernation is rolled. The ligule is membranous and frayed, and auricles are absent. The sheath is also typically hairy.
Root System
Fine, fibrous root system. It lacks rhizomes or stolons. Its primary survival mechanism is rapid autumn or early spring establishment to deplete soil moisture before perennials wake.
Growing Information
Origin Region
Native to Europe, southwestern Asia, and northern Africa; highly invasive in North America, particularly the Intermountain West.
Growth Habit
Bunch-type, erect to spreading, rapidly colonizing disturbed soil via heavy seed production.
Sunlight & Water Needs
Full sun preferred; highly drought-adapted. Thrives in dry, sandy, or loamy soils and dominates in areas with low annual precipitation and high summer heat.
Mowing & Maintenance
Not maintained as turf. Mowing is recommended before seed heads form to prevent spread. Frequent close mowing can reduce seed production but rarely eradicates the plant. Maintenance level is technically nil as it is a weed.
Special Characteristics
Notorious for its dry, highly flammable biomass that increases wildfire frequency. The barbed seeds (awns) can injure the mouths and eyes of livestock and get stuck in pet fur.
Ecological Information
Highly invasive and ecological harmful; displaces native bunchgrasses like Bluebunch Wheatgrass. Provides minimal forage value when green but is avoided once seed heads harden. Forms monocultures that alter nitrogen cycling.