Large Crabgrass (Hairy Crabgrass)
Digitaria sanguinalis · Warm-season, Annual, C4 photosynthetic pathway
Grass Family
Poaceae, Panicoideae, Tribe Paniceae
Grass Category
Invasive/Weed Grass (occasionally used for forage in specific agricultural contexts)
Variety / Cultivar
None (Wild type common weed)
Hardiness Zones
USDA Zones 2-11 (as an annual); dies off with the first hard frost but leaves behind thousands of seeds that remain viable for years.
About This Grass
An aggressive, low-growing annual weed that thrives in hot weather. It features a pale green to light green color with a coarse texture. If left unmowed, it can reach 1-2 feet, but typically stays low. Seed heads are digital (finger-like) spikes emerging from the top of the stem.
Blade Characteristics
Coarse blade width (>4mm), reaching up to 10-15mm wide. Blades are flat, tapering to a sharp point. Distinctive hairy (pubescent) surface and leaf sheaths. Vernation is rolled. Ligule is tall and membranous with jagged edges; auricles are absent.
Root System
Shallow, fibrous root system that establishes extremely quickly from seed. Can root at lower stem nodes wherever they touch moist soil, creating a secondary root support system.
Growing Information
Origin Region
Native to Europe and Asia; highly invasive and naturalized throughout North America and temperate/tropical regions worldwide.
Growth Habit
Prostrate or decumbent growth habit; spreads via tillering and by rooting at the nodes (stolons). Forms thick mat-like clumps.
Sunlight & Water Needs
Full sun preferred; thrives in high-heat conditions with moderate to high water availability, but highly drought-tolerant once established in disturbed soils.
Mowing & Maintenance
Not applicable as a cultivated lawn; in a turf setting, it is managed by maintaining lawn height at 3-4 inches to shade out crabgrass seeds. High maintenance to eradicate, involving pre-emergent or post-emergent herbicides.
Special Characteristics
Extremely high wear tolerance; prolific seed producer (up to 150,000 seeds per plant); salt tolerant; easily outcompetes desirable turf grasses in thin or under-fertilized lawns.
Ecological Information
Introduced/Invasive status in North America. Provides minimal wildlife value (some small birds eat seeds), but primarily considered a nuisance that disrupts native biodiversity and lawn aesthetics. Excellent at soil stabilization in disturbed areas but highly aggressive.