Invasive Species: Microstegium vimineum, Japanese Stiltgrass
Japanese stiltgrass invades forested habitats, out-competing native understory plants. It is a delicate, sprawling, annual grass that is 0.5 to 3.5 ft. (0.2 to 1.1 m) in height. The leaves are pale green, alternate, lance-shaped, 1 to 3 in. (2.5 to 7.6 cm) long, and asymmetrical, with shiny, off-center midribs. Stems usually droop. Flowering occurs in late summer, when delicate flower stalks develop in the axils of the leaves or at the apexes of the stems. Fruit is yellow to red and 0.1 to 0.12 in. (2.8 to 3.0 mm) long and matures in about two weeks in September and October. Most commonly an invader of forested floodplains, Japanese stiltgrass also grows in ditches, forest edges, fields, and trails. It is shade tolerant and can displace vegetation native to floodplains. Japanese stiltgrass is native to Asia and was accidentally introduced in North America sometime around 1920. In the past, it was used as packing material for porcelain, possibly explaining its accidental introduction.
What are invasive species, and why should we be concerned about them?
Taxonomy: Scientific and Common Names for This Species
Cyperales > Poaceae > Microstegium vimineum (Trin.) A. Camus
Synonym(s): Nepalese browntop, Japanese grass, Mary's grass, Nepalgrass
Microstegium vimineum - USDA PLANTS Profile
Distribution Maps
Japanese stiltgrass - The reported distribution of this invasive species across the United States (Source: Invasive Plant Atlas of the United States)
Up-to-the-minute distribution maps and why they are important
Reporting This Invasive Species
What is the best way to report the occurrence of an invasive species?
How to report an invasive species sighting to EDDMapS - Early Detection & Distribution Mapping System
EDDMapS - Report an invasive species to EDDMapS.
County Extension Offices - Find your county Extension office on this map provided by USDA.
How to Identify
This invasive species can be identified by looking for the characteristics described in the paragraphs that follow.
Grass
Japanese stiltgrass is a delicate, sprawling, annual grass that is 0.5 to 3.5 ft. (0.2 to 1.1 m) in height.
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| David J. Moorhead, University of Georgia, bugwood.org | John M. Randall, The Nature Conservancy, bugwood.org |
Foliage
The leaves are pale green, alternate, lance-shaped, 1 to 3 in. (2.5 to 7.6 cm) long, and asymmetrical, with shiny, off-center midribs. Stems usually droop.
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| David J. Moorhead, University of Georgia, bugwood.org | Ted Bodner, Southern Weed Science Society, bugwood.org |
Flower
Flowering occurs in late summer, when delicate flower stalks develop in the axils of the leaves or at the apexes of the stems.
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| Leslie J. Mehrhoff, University of Connecticut, bugwood.org | bugwood.org |
Fruit
Fruit is yellow to red and 0.1 to 0.12 in. (2.8 to 3.0 mm) long and matures in about two weeks in September and October.
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| Steve Hurst, USDA NRCS PLANTS Database, bugwood.org | bugwood.org |
Native Species That Resemble Japanese Stiltgrass
- Images at invasive.org
| bugwood.org | bugwood.org |
- Images at invasive.org
| bugwood.org | bugwood.org |
Additional Images for Japanese Stiltgrass
Japanese stiltgrass - Images at invasive.org
Learning Resources for Japanese Stiltgrass
Microstegium vimineum Identification Card - U.S. Fish and Wildlife Service
Microstegium vimineum Fact Sheet - U.S. Fish and Wildlife Service
Microstegium vimineum Fact Sheet - UW-Extension Weed Science
Additional Information, Biology, Control and Management Resources
Control and management recommendations vary according to individual circumstances. Location, habitat, weather, and a variety of other conditions are factors that help determine the best treatment choice. To find the safest and most effective treatment for your situation, consult your state's land-grant institution. If you will use chemicals as part of the control process, always refer to the product label.
United States Land Grant University System - Find your Land Grant University's College of Agriculture, University Cooperative Extension Service, or other related partner on this map provided by USDA.
Fact Sheet - Pennsylvania Department of Conservation and Natural Resources
A Field Guide for the Identification of Invasive Plants in Southern Forests - USDA Forest Service
A Management Guide for Invasive Plants of Southern Forests - USDA Forest Service
Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
Southeast Exotic Pest Plant Council Invasive Plant Manual - Southeast Exotic Pest Plant Council (SE-EPPC)
Element Stewardship Abstract - The Nature Conservancy
Weeds Gone Wild: Alien Plant Invaders of Natural Areas - Plant Conservation Alliance
Invasive Plant Atlas of New England - University of Connecticut
Weed of the Week - USDA Forest Service
