Yellow Foxtail
Setaria pumila · Warm-season, Annual, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass, Low-quality Forage
Variety / Cultivar
Common Yellow Foxtail (wild-type)
Hardiness Zones
USDA Hardiness Zones 3-11; emerges when soil temperatures reach 60°F and dies off with the first hard frost of winter.
About This Grass
A coarse summer annual weed with a yellowish-green color. It grows in loose clumps, reaching 1 to 3 feet in height. Known for its distinct 'bristly' cylindrical seed head (spikelike panicle) that turns yellowish at maturity.
Blade Characteristics
Coarse width (>4mm), reaching 12mm; flat shape with a pointed tip; light green to lime green color; rolled vernation; distinct long, silky hairs near the base on the upper leaf surface; ligule is a fringe of hairs; auricles are absent.
Root System
Shallow, fibrous root system; high establishment speed through prolific seeding; does not form a dense sod and has low thatch tendency.
Growing Information
Origin Region
Native to Europe and Asia; highly invasive and naturalized throughout North America, performing best in disturbed soils and agricultural fields.
Growth Habit
Bunch-type (clump-forming); typically grows upright or sprawling via decumbent branching but does not possess rhizomes or stolons.
Sunlight & Water Needs
Full Sun (6+ hours); thrives in moist or dry conditions but prefers nitrogen-rich, well-watered agricultural soils; high drought tolerance once established; pH 5.5 to 7.5.
Mowing & Maintenance
Maintenance level is low as it is a weed; can be mowed at 2-3 inches to prevent seed head formation, though it can adapt to lower mowing heights by tillering; high fertilization promotes its growth over turfgrass.
Special Characteristics
High seed production (up to 12,000 seeds per plant); tolerant of low-mowing; rapid growth cycle in summer heat; can cause mouth sores in livestock due to sharp awns in mature seed heads.
Ecological Information
Introduced/Invasive status in North America; low wildlife value (some small birds eat seeds); colonizes disturbed sites rapidly; often found as a weed in new lawn seedings or poorly maintained pastures.