Crabgrass
Digitaria sanguinalis · Warm-season, Annual, C4 photosynthetic pathway
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass
Variety / Cultivar
Common Large Crabgrass (Digitaria sanguinalis)
Hardiness Zones
USDA Zones 3-11; dies back completely after the first hard frost/freeze, leaving behind brown patches and thousands of seeds for the following year.
About This Grass
A low-growing, spreading annual weed that forms unsightly yellowish-green mats. It emerges in late spring/early summer, thriving in heat. Seed heads are digital (finger-like) spikes, usually 3-7 per stem, carrying hundreds of seeds.
Blade Characteristics
Coarse blades, 5-10mm wide; flat with a pointed tip; pale to medium green; rolled vernation in the bud; leaf blades and sheaths are typically covered in dense, long hairs (pilose). Large membranous ligules; auricles are absent.
Root System
Shallow, fibrous root system that establishes quickly. While shallow, its ability to root at stem nodes allows it to monopolize surface moisture and form a dense, competitive mat that smothers desirable turf.
Growing Information
Origin Region
Native to Europe and Asia, now naturalized worldwide in temperate and tropical regions; aggressive in USDA zones 3-11.
Growth Habit
Stoloniferous and decumbent; stems grow horizontally along the ground and can root at the nodes (nodes are swollen and often purple-tinged).
Sunlight & Water Needs
Full sun preferred (very shade intolerant); high drought tolerance once established; thrives in compacted, poorly managed soils with frequent light watering.
Mowing & Maintenance
Low maintenance; it easily survives low mowing heights (down to 0.5 inches). Control requires pre-emergent herbicides in early spring or post-emergent selective herbicides. Mowing to 3+ inches for desirable turf helps shade out crabgrass seedlings.
Special Characteristics
Prolific seed producer (up to 150,000 seeds per plant); excellent heat and traffic tolerance; allelopathic tendencies that inhibit the growth of neighboring plants.
Ecological Information
Introduced/Invasive in manicured landscapes; seeds provide food for small birds and rodents in wild settings, but it is generally considered a nuisance that decreases biodiversity in native North American grasslands.