Large Crabgrass
Digitaria sanguinalis · Warm-season, Annual, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass, Lawn/Turf Weed
Variety / Cultivar
Wild Type (Common Large Crabgrass)
Hardiness Zones
USDA Hardiness Zones 3-10; strictly an annual that is killed by the first hard frost, surviving winters only as seeds in the soil.
About This Grass
An annual grassy weed with a sprawling, prostrate to ascending growth habit. Can grow up to 1-2 feet tall if left unmowed, but usually forms flat, crab-like rosettes in lawns. Color is light to medium green, often with purplish or reddish tints at the base of stems. Texture is coarse. Produces finger-like (digitate) raceme seed heads at maturity.
Blade Characteristics
Blades are medium-coarse in width (4-10 mm), flat, pointed at the tips, and light to bright green in color, sometimes tinged with purple. Rolled in the bud (vernation). Features a membranous, jagged ligule, and auricles are absent. The collar is broad and continuous with prominent hairs.
Root System
Fibrous root system with shallow roots, though lower nodes can produce secondary roots where they touch the soil. Rapid establishment from seed in spring, poor drought tolerance during severe dry spells but highly resilient in thin turf.
Growing Information
Origin Region
Europe and temperate Asia; now globally naturalized throughout temperate and tropical regions
Growth Habit
Stoloniferous and branching; stems root at the lower nodes, spreading outward from a central crown in a sprawling or prostrate mat-forming habit
Sunlight & Water Needs
Requires full sun; highly intolerant of dense shade. Prefers moist, warm soils but can survive moderate drought by going dormant or setting seed quickly. Thrives in compacted, poor-drainage soils with neutral to slightly acidic pH.
Mowing & Maintenance
Responds well to low mowing by spreading horizontally and producing seed heads below the mowing height. High maintenance as a weed to be removed; controlled via pre-emergent herbicides in early spring or post-emergent selective herbicides.
Special Characteristics
Extremely high seed production allows it to rapidly invade thin, stressed lawns. Poor traffic tolerance compared to well-established turfgrasses, but highly competitive in bare spots and poorly managed turf. Excellent colonizer of disturbed earth.
Ecological Information
Introduced species in North America, often considered a noxious weed in managed turf. Provides minimal wildlife food value compared to native grasses, though seeds are eaten by some ground-feeding birds. Its aggressive spreading nature crowds out desirable lawn grasses.