Japanese Stiltgrass
Microstegium vimineum · Warm-season, Annual, C4 grass
AI-generated identification · may be incorrect
Grass Category
Invasive/Weed Grass
Hardiness Zones
USDA Hardiness Zones 5-9, thrives in temperate to subtropical regions with adequate moisture.
Grass Family
Poaceae, subfamily Panicoideae, tribe Andropogoneae
Variety / Cultivar
Wild type (No specific cultivated varieties)
About This Grass
An annual grass with a sprawling, branching habit, growing up to 1-3 feet tall. It features pale green to bright green leaves and forms dense, uniform carpets that can smother native vegetation. Seed heads are slender, spike-like racemes.
Blade Characteristics
Blades are short, lanceolate (about 1-3 inches long and 4-15mm wide), flat, asymmetrical, with a prominent silvery stripe of hairs along the midrib on the upper surface. Vernation is rolled. Ligule is a membranous fringe. Auricles are absent.
Root System
Shallow, fibrous root system with roots often emerging from lower stem nodes that touch the ground. Establishes rapidly from seed, forming a loose sod.
Growing Information
Origin Region
Asia (India, China, Japan, Korea, Malaysia); naturalized extensively in the eastern United States
Growth Habit
Stoloniferous, forming dense mats; sprawling stems root at the nodes
Sunlight & Water Needs
Highly adaptable to both full sun and deep shade. Prefers moist, shaded soils such as floodplains, forest edges, and damp woods, but tolerates a range of soil types.
Mowing & Maintenance
Maintained as a weed rather than a turf grass; easily controlled by frequent mowing or hand-pulling before seed set in late summer.
Special Characteristics
Extremely invasive, highly shade-tolerant for a C4 grass, poor wear tolerance compared to established turf, highly capable of displacing native understory plants in forests.
Ecological Information
Introduced invasive species in North America. Provides little value to native wildlife, alters soil chemistry and fire regimes, and heavily disrupts forest understory ecosystems.