Green Foxtail
Setaria viridis · Warm-season, Annual, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass, Agricultural Weed
Variety / Cultivar
Wild type (no specific named agricultural cultivars commonly utilized)
Hardiness Zones
Widely adaptable across USDA Hardiness Zones 3 through 9, functioning strictly as a warm-season summer annual that dies with the first hard frost.
About This Grass
An annual grass forming dense, coarse clumps reaching heights of 1 to 3 feet when mature. Displays a vibrant green color during the growing season, turning yellowish-brown at maturity. Characterized by prominent, bristly, cylindrical, nodding or drooping panicle seed heads resembling bottle brushes or foxtails.
Blade Characteristics
Medium-to-coarse width blades (4-10 mm), flat, linear-lanceolate with pointed tips. Color is bright to medium green, sometimes with a slightly rough texture. Vernation is rolled in the bud. Ligule is a fringe of hairs. Auricles are absent. Collar is narrow and continuous.
Root System
Fibrous root system of moderate depth. Establishes rapidly from seed in disturbed soils. Does not form a sod or rhizomes, relying entirely on heavy seed production for propagation and survival from year to year.
Growing Information
Origin Region
Eurasia; now widely naturalized throughout temperate and subtropical regions globally, commonly found in disturbed soils, agricultural fields, and waste areas
Growth Habit
Bunch-type (clump-forming) annual, upright growth with multiple stems arising from the base
Sunlight & Water Needs
Requires full sun for optimal growth; highly intolerant of heavy shade. Moderate to high drought tolerance once established, though it thrives best in moist, fertile soils. Adaptable to a wide range of soil pH and soil types, frequently colonizing compacted or disturbed ground.
Mowing & Maintenance
Typically managed as a weed rather than a cultivated turfgrass. Cannot withstand frequent close mowing, which prevents seed production. Requires high maintenance or chemical intervention if unwanted in lawns, pastures, or crop fields.
Special Characteristics
Possesses prolific seed production allowing rapid weed spread and high competition against desirable turf or crops. Exhibits low wear tolerance for formal turf use but strong capability to colonize disturbed bare earth for erosion control.
Ecological Information
Introduced species in North America acting primarily as an agricultural weed, though its seeds provide an important food source for ground-feeding birds and small mammals. Helps stabilize disturbed soil temporarily but is generally considered invasive in agricultural and managed turf contexts.