Crabgrass
Digitaria ischaemum · Warm-season, Annual, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass
Variety / Cultivar
Wild type (Smooth crabgrass / Large crabgrass)
Hardiness Zones
USDA Hardiness Zones 3-10, extremely heat tolerant, dies completely with the first hard frost in northern zones.
About This Grass
An aggressive, coarse-textured, light to medium green annual grassy weed that germinates in spring, grows rapidly during hot summer months, and forms dense patches that crowd out desirable turfgrasses. Reaches up to 6-24 inches if unmowed. Produces distinctive finger-like or crab-claw-like seed heads in late summer.
Blade Characteristics
Coarse texture (>4mm wide), flat, pointed tips, light green to blue-green color, rolled in the bud (vernation), membranous ligule, lacks auricles, prominent veins along the center of the leaf blade.
Root System
Fibrous and relatively shallow roots, but nodes that touch the soil can easily root and form new plants, resulting in rapid establishment and difficult eradication once mature.
Growing Information
Origin Region
Europe and Eurasia, now widely naturalized throughout temperate and tropical regions globally, performing best in warm, disturbed soils.
Growth Habit
Stoloniferous and spreading outward in a sprawling, mat-forming, or prostrate rosette pattern.
Sunlight & Water Needs
Requires full sun, cannot tolerate dense shade. Moderate to high water needs for germination and rapid growth, but exhibits fair drought tolerance by entering a semidormant state during extreme dry spells. Thrives in compacted, poor-drainage, warm soils with pH ranging from 6.0 to 7.0.
Mowing & Maintenance
High maintenance weed; easily survives low mowing heights by growing horizontally close to the ground. Requires pre-emergent herbicide applications in early spring, post-emergent controls during summer, and thick turf maintenance to prevent establishment.
Special Characteristics
Exceptional heat and drought tolerance during summer, highly invasive in thin lawns, poor wear tolerance to heavy traffic compared to established turf, excellent at colonizing bare soil and erosion-prone areas.
Ecological Information
Introduced exotic weed species in North America. Provides minimal wildlife forage compared to native grasses, but serves as a minor food source for seed-eating birds. Highly aggressive and considered a nuisance weed in residential lawns and agricultural fields.