Crabgrass (Large/Hairy Crabgrass)
Digitaria sanguinalis · Warm-season, Annual, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Invasive/Weed Grass
Variety / Cultivar
Common wild type (Large Crabgrass)
Hardiness Zones
Grows as a summer annual in USDA Zones 2-11. It is killed by the first hard frost but leaves behind thousands of viable seeds for the following year.
About This Grass
A coarse, light-green annual weed that emerges in late spring. It grows in a star-like, decumbent pattern, hugging the ground. If unmowed, it can reach 2 feet in height. Seed heads are finger-like spikes (digitate) emerging from a common point.
Blade Characteristics
Coarse blade width (5-10mm); flat shape with a pointed tip. Pale to medium green color. Vernation is rolled in the bud. Notable for having long, stiff hairs on both the leaf blades and sheaths. Ligule is membranous; auricles are absent.
Root System
Fibrous and shallow but extremely vigorous. It spreads by rooting at the lower stem nodes (culms) where they touch the soil. Dense mat formation allows it to outcompete turf; low thatch tendency as it is an annual.
Growing Information
Origin Region
Native to Europe and Asia; widely naturalized throughout North America and worldwide in temperate and tropical zones.
Growth Habit
Prostrate, spreading bunch-type that root at the nodes (stoloniferous-like behavior); forms dense, radiating mats.
Sunlight & Water Needs
Full sun (highly shade intolerant). Requires moisture for germination but is extremely drought tolerant once established. Thrives in compacted soils and high-heat environments.
Mowing & Maintenance
Managed by maintaining turf at 3-4 inches to shade out seedlings. In lawns, it is usually treated with pre-emergent herbicides in early spring or post-emergent selective herbicides. High maintenance effort required for eradication.
Special Characteristics
Exceptional traffic tolerance; highly opportunistic in bare or thin lawn spots. Its ability to root at nodes makes it difficult to pull manually. Allelopathic properties may inhibit the growth of surrounding desirable grasses.
Ecological Information
Introduced/Invasive in managed turf. Provides seeds for ground-feeding birds (such as finches and sparrows) and forage for some livestock, but generally considered a nuisance that decreases biodiversity in lawns and pastures.