Large Crabgrass
Digitaria sanguinalis · Warm-season, Annual, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass
Variety / Cultivar
Not applicable (wild-type invasive weed)
Hardiness Zones
Grown as an annual in USDA Zones 2-11. It is extremely heat tolerant but has zero cold tolerance; the plant dies off with the first frost, leaving brown patches and fertile seeds for next year.
About This Grass
A coarse, prostrate annual weed often appearing prominently in turf during summer. It has a light green to lime-green color, low-growing spreading habit, and produces finger-like seed heads (spikes) from the stem tips. It thrives in high heat and thin turf areas.
Blade Characteristics
Coarse blade width (5-10mm); flat shape with a pointed tip. Pale green to yellowish color. Vernation is rolled in the bud. Blades are often covered in fine, stiff hairs (pilose) especially at the sheath, which distinguishes it from smooth crabgrass. Ligule is membranous and tall; auricles are absent.
Root System
Fibrous and shallow, but aggressive. Spreads rapidly across the surface through stolon-like stems that root at the nodes. Lacks rhizomes; does not form a permanent sod as it dies off completely after the first hard frost.
Growing Information
Origin Region
Native to Europe and Asia; widely naturalized and invasive throughout North America and temperate/tropical regions globally.
Growth Habit
Stoloniferous and branching; forms a prostrate, radial mat-like clump. Nodes can root upon contact with soil.
Sunlight & Water Needs
Full Sun (requires high light to germinated/thrive); high drought tolerance once established. Prefers moist soils but can survive and outcompete turf in dry, compacted areas. Adapts to many soil pH levels.
Mowing & Maintenance
Maintenance involves prevention rather than cultivation. It can survive mowing as low as 0.5 inches by growing prostrate. Recommendations: High mowing (3-4") for surrounding turf to shade out seedlings, and use of pre-emergent herbicides in early spring.
Special Characteristics
Extremely high wear tolerance due to its low, thick growth; high seed production (up to 150,000 seeds per plant); ability to invade thin lawn areas; allelopathic tendencies that may inhibit surrounding desirable grasses.
Ecological Information
Introduced/Invasive status in the US. Provides seeds for some ground-feeding birds, but generally considered a nuisance that reduces biodiversity in home lawns. Often found in companion with disturbed soils, compacted turf, or thin patches of Kentucky Bluegrass.