Large Crabgrass (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
Hardiness Zones
USDA Zones 2-11; dies back completely after the first hard frost but survives through prolific seed production (thousands of seeds per plant).
About This Grass
A coarse, pale to medium green annual weed that grows in a low, star-shaped pattern. Stems are often purplish at the base. It remains low under mowing but can reach 2 feet in height if left untouched, producing finger-like spiked seed heads.
Blade Characteristics
Coarse blade width (5-10mm), flat shape with pointed tips, light to medium green. Features a distinctive hairy leaf sheath and blade (especially at the base). Rolled vernation, membranous tall ligule, and no auricles. Leaves often have a prominent midvein.
Root System
Shallow, fibrous root system. Highly effective at establishment; stems root easily at lower nodes (culms) when they touch the soil, leading to rapid expansion and high thatch-like accumulation.
Growing Information
Origin Region
Native to Europe and Asia; widely naturalized and invasive throughout North America and worldwide temperate/tropical regions.
Growth Habit
Bunch-type/Prostrate spreading; aggressive tillering with stems that can root at the nodes (decumbent habit) creating dense mats in under-maintained soil.
Sunlight & Water Needs
Full sun preferred; high drought tolerance once established. Thrives in compacted soils, thin turf, and hot, dry conditions where desirable grasses struggle.
Mowing & Maintenance
High maintenance for control. For lawns: mow high (3-4 inches) to shade out seeds. Requires pre-emergent herbicides in early spring and post-emergent selective herbicides if established. Thrives in low heights by growing prostrate.
Special Characteristics
Extremely high wear tolerance; opportunistic; identifies and fills bare spots in lawns; allelopathic tendencies that can suppress nearby plants; highly resistant to many common lawn stresses.
Ecological Information
Introduced species; considered a noxious weed in ornamental turf but seeds provide food for small birds (finches, sparrows). Poor soil stabilization compared to perennials; often acts as a pioneer species on disturbed ground.