Japanese Stiltgrass
Microstegium vimineum · Warm-season, Annual, C4
AI-generated identification · may be incorrect
Grass Category
Invasive/Weed Grass
Hardiness Zones
USDA Hardiness Zones 5 to 9. Tolerates cold winters as seeds survive in the soil.
Grass Family
Poaceae, subfamily Panicoideae, tribe Andropogoneae
Variety / Cultivar
None (wild species)
About This Grass
An annual grass that grows in sprawling mats up to 3 feet tall or long. Light to medium green color, turning yellowish or purplish in autumn before dying back with the first frost. Delicate texture with weak stems.
Blade Characteristics
Blades are flat, lance-shaped, 3 to 8 cm long, and 5 to 15 mm wide, with a distinctive silvery-reflective stripe of off-center hairs down the middle of the upper surface. Ligule is a membranous fringe, auricles absent.
Root System
Shallow, fibrous root system with roots frequently forming at the lower nodes where stems touch the ground. Fast establishment from seed, poor wear tolerance, pulls out of the ground easily.
Growing Information
Origin Region
Native to Asia (Japan, China, Korea, India, Malaysia); naturalized extensively in the eastern United States and parts of temperate North America.
Growth Habit
Stoloniferous, forming loose mats, rooting at lower nodes, spreading rapidly by prolific seed production.
Sunlight & Water Needs
Highly shade tolerant, but also grows in full sun. Thrives in moist, shaded soils such as floodplains, forest understories, along paths, and ditches. Low drought tolerance.
Mowing & Maintenance
Requires frequent low mowing or weed-whacking to prevent flowering and seed set. Considered a high-nuisance weed requiring eradication rather than maintenance.
Special Characteristics
Extremely invasive, crowds out native understory vegetation, low wear tolerance, high adaptability to deep shade, spreads rapidly via contaminated soil and mowing equipment.
Ecological Information
Aggressive invasive species in North America. Provides little to no value for native wildlife and negatively impacts forest regeneration and native plant diversity.