Purple Nutsedge
Cyperus rotundus · Warm-season perennial sedge, C4 photosynthetic pathway
Grass Family
Cyperaceae, subfamily Cyperoideae
Grass Category
Invasive/Weed Grass (technically a sedge)
Variety / Cultivar
Wild type species, highly resilient and aggressive weed variety
Hardiness Zones
USDA Hardiness Zones 7 through 11, highly sensitive to freezing temperatures which kill topgrowth, though underground tubers survive in milder climates.
About This Grass
Forms dense, upright clumps of bright green to yellowish-green foliage with distinct triangular stems. Can grow up to 15 to 40 cm tall when unmowed. Features distinctive umbrella-like clusters of brownish-purple spikelets or seed heads at the terminal ends of triangular flowering stems.
Blade Characteristics
Leaves are basal, linear, glossy, V-shaped or channeled in cross-section, medium width (3 to 8 mm), with pointed tips and smooth margins. Stems are solid and triangular in cross-section, distinguishing it from true grasses which have round or flattened stems.
Root System
Extensive, deep root system characterized by fibrous roots, underground stolons, and complex chains of dark, hard tubers (nutlets) that store energy and water, making it extremely difficult to eradicate.
Growing Information
Origin Region
Africa, southern and central Europe, and southern Asia; now naturalized worldwide in tropical, subtropical, and warm temperate regions
Growth Habit
Rhizomatous and tuber-bearing, producing underground chains of nutlike tubers and fibrous roots, spreading rapidly to form dense patches
Sunlight & Water Needs
Thrives in full sun and high moisture conditions; frequently found in poorly drained soils, over-irrigated lawns, and wet areas, though established tubers exhibit high drought tolerance. Prefers moist, fertile soils but adapts to various soil types.
Mowing & Maintenance
Grows faster than many turfgrasses, especially after rain, requiring frequent mowing. Mowing at standard turf heights does not control it, as it rapidly regrows from underground tubers. High maintenance required for removal.
Special Characteristics
Exceptional resistance to standard selective herbicides due to its tuber network; highly invasive in lawns, agricultural fields, and gardens; tolerates compaction and poor drainage; difficult to crowd out.
Ecological Information
Considered one of the world's worst agricultural weeds; outcompetes native flora and turfgrasses in moist environments; provides minimal desirable wildlife value compared to true grasses; spreads aggressively via contaminated soil, equipment, and underground tubers.