Purple Nutsedge
Cyperus rotundus · Warm-season, Perennial, C4 sedge
Grass Family
Cyperaceae, subfamily Cyperoideae
Grass Category
Invasive/Weed Grass
Variety / Cultivar
Wild type (not cultivated)
Hardiness Zones
USDA Hardiness Zones 7-11; highly sensitive to freezing temperatures which can kill surface growth, though tubers survive deeper in the soil.
About This Grass
Forms dense colonies with triangular, solid stems growing 6 to 40 inches tall. Features basal leaves with bright green to dark green blades. Produces distinctive reddish-brown to purple inflorescences consisting of umbrella-like clusters of spikelets at the end of a triangular stem.
Blade Characteristics
Blades are narrow (2-6 mm wide), linear, flat or channeled, pointed at the tips, and mostly basal. Vernation is folded. Ligule is a fringe of hairs. Auricles are absent. Stems are distinctly triangular in cross-section.
Root System
Extensive, deep root system featuring fibrous roots connected to underground rhizomes that terminate in hard, dark brown or black tubers (nutlets). Extremely fast establishment from tubers, which makes manual removal very difficult.
Growing Information
Origin Region
Native to Africa and southern/central Eurasia; naturalized worldwide in tropical and warm temperate regions
Growth Habit
Rhizomatous and tuber-bearing, spreading aggressively via underground stolons and chains of small, dark tubers (nutlets)
Sunlight & Water Needs
Thrives in full sun; highly tolerant of moist to wet soils, poor drainage, and temporary flooding, but also exhibits high drought tolerance once established. Prefers acidic to neutral soils (pH 5.0-7.0) but adapts to various soil types.
Mowing & Maintenance
High maintenance weed; tolerates low mowing and bounces back quickly by shifting growth resources to underground tubers. Mowing does not control it; requires specialized selective herbicides or manual digging of entire tuber chains.
Special Characteristics
Exceptional wear tolerance due to rapid underground regeneration. Highly invasive in turfgrass, gardens, and agricultural fields. Extremely difficult to eradicate because breaking the stem or pulling the plant leaves behind tubers that sprout new shoots.
Ecological Information
Considered one of the world's worst agricultural weeds. Provides limited forage value for some wildlife, but its aggressive nature often crowds out native plants and desirable turfgrasses. Spreads primarily through human transport of contaminated soil and agricultural equipment.