Microstegium vimineum, commonly known as Japanese stiltgrass, packing grass, or Nepalese browntop, is an annual grass that is common in a wide variety of habitats and is well adapted to low light levels. It has become an invasive species throughout parts of the world, most notably North America.
Distribution Microstegium viminium is native to many parts of Asia from Turkey in the west to Japan in the east. In East Asia, it is found in China, Japan, the Russian Far East, North Korea, South Korea, and Taiwan. In Southeast Asia, its native range includes Malaysia, Myanmar, the Philippines, Thailand, Laos, and Vietnam. In South Asia, it occurs in Bhutan, India, and Nepal. In West Asia, particularly in the Caucasus and the Black Sea and Caspian Sea coasts, it can be found in Turkey, Georgia, Iran, and in Sochi in Russia.
The species has also been introduced extensively beyond its native range. In North America, it is established throughout the Midwestern United States, the Southeastern United States, the West South Central United States, the Northeastern United States, and southern Ontario in Canada.
Description It typically grows to heights between and is capable of rooting at each node. The plant flowers in late summer and produces its seeds in the form of a caryopsis shortly thereafter. It is quite similar to and often grows along with the North American grass Leersia virginica, but L. virginica lacks the distinctive silver stripe on the center of the leaf that is present on Japanese stiltgrass and also flowers one to two months earlier.
Invasiveness The plant was accidentally introduced into the U.S. state of Tennessee around 1919 as a result of being used as a packing material in shipments of porcelain from China. It has spread throughout the Southeastern U.S. and is now found in 26 states.USDA, NRCS. 2012. The PLANTS Database (http://plants.usda.gov, 19 August 2012). National Plant Data Team, Greensboro, NC 27401-4901 USA. Microstegium vimineum most commonly invades along roads, floodplain and other disturbed areas, but will also invade undisturbed habitats.Redman, D.E. 1995. Distribution and habitat types for Nepal Microstegium (Microstegium vimineum) in Maryland and the District of Columbia. Castanea, 60:270-275Cole, P.G. and J.G. Weltzin. 2005. Environmental correlates of the distribution and abundance of Microstegium vimineum in east Tennessee. Southeastern Naturalis, 3:545-563.Moretensen, D.A., E.S.J. Rauschert, A.N Nord and B.P. Jones. 2009. Forest roads facilitate the spread of invasive plants. Invasive Plant Science and Management. 2:191-199 White-tailed deer, which do not browse the grass, may facilitate spread by browsing on native species and thereby reducing competition for the exotic plant. Invasion of Microstegium can reduce growth and flowering of native species,Bauer, J.T. and Flory, S.L. 2011. Suppression of the woodland herb Senna hebecarpa by the invasive grass Microstegium vimineum. American Midland Naturalist. 165:105-115. suppress native plant communities,Flory, S.L. and K. Clay. 2010. Non-native grass invasion alters native plant composition in experimental communities. Biological Invasions 12:1285-1294 alter and suppress insect communities,Simao, M.C., S.L. Flory, and J.A. Rudgers. 2010. Experimental plant invasion reduces arthropod abundance and richness across multiple trophic levels. Oikos 119:1553-1562. slow plant successionFlory, S.L. and K. Clay. 2010. Non-native grass invasion suppresses forest succession. Oecologia 164:1029-1038. and alter nutrient cycling.Ehrenfeld, J.G. 2003 Effects of exotic plant invasions on soil nutrient cycling processes. Ecosystems 6:503–523Lee, M., S.L. Flory, and R. Phillips. 2012. Positive feedbacks to growth of an invasive grass through alteration of nitrogen cycling. Oecologia. DOI: 10.1007/s00442-012-2309-9 Removal of Microstegium can lead to recovery of native plant communities.Flory, S.L. 2010. Management of Microstegium vimineum invasions and recovery of resident plant communities. Restoration Ecology. 18:103-112Flory, S.L. and K. Clay. 2009. Invasive plant removal method determines native plant community responses. Journal of Applied Ecology. 4:434-442.DeMeeste, J.E., Richter, D.D. 2010. Restoring restoration: removal of the invasive plant Microstegium vimineum from a North Carolina wetland. Biological Invasions 12:781–793
As this grass is an annual, in order to control it, mowing must be performed before the plants go to seed.
This plant has been put on the European list of invasive alien species, meaning that it cannot be imported into or traded in the European Union.
Management
It is typically argued that ecological communities with a higher species diversity are able to resist the growth of invasive species . However, the presence of Microstegium Vimineum in recent studies has raised the question of its role as a highly competitive species in these diverse communities. A recent study conducted in North Carolina utilised a two year field experiment to measure the competitive effect and resistance. Results found that the use of diversity-mediated resistance did not result in the deterrence of growth and spread by M. Vimineum due to its strong presence . The results indicate that for the preservation of native species, the invader in this case, M. Vimineum, would have to be removed completely. This has highlights the consequences of invasive species and shows how imperative accessible and safe management options for the overall health of native ecosystems.
As the growth and spread of Microstegium Vimineum increases amongst residential properties there are increasing studies on safe and accessible control methods to protect native plant communities. A study published in 2025 compared the use of glyphosate against vinegar finding glyphosate was effective in removing nearly all M. Vimineum but resulted in less herbaceous plant communities . Vinger was found to only remove around 55% of the M. Vimineum but was able to maintain richness and diversity. On the other hand a study published in 2026 looked into non-herbicide options including shade and sawdust amendments which can suppress M. Vimineum growth whilst also promoting competition for native plant competition. Both studies shows the importance of using safe and accessible management strategies that can be used to control the growth of an invasive species whilst protecting the native plant community.
Ecology Despite its invasive status in the United States, there are some benefits to stiltgrass. It can serve as a host plant for some native satyr butterflies, such as the Carolina satyr Hermeuptychia sosybius and the endangered Mitchell's satyr Neonympha mitchellii. In the absence of other habitat, stiltgrass is more preferable to have than nothing, providing cover for native amphibians such as wood frogs and toads. Stiltgrass is also unfavorable habitat for ticks due to higher temperature and lower humidity, leading to increased mortality for them. The dead fallen stems of stiltgrass can provide shelter for rodents to the point where aerial predators (owls and hawks) cannot catch them.
White-tailed deer do not eat stiltgrass and help its dominance by eating competing plants. However, stiltgrass can be outcompeted by other aggressive species such as annual ryegrass, Virginia cutgrass, and jewelweed. Stiltgrass can also be controlled by regular fires, thick leaf litter, and succession of taller herbs.
Another species that Microstegium Vimineum indirectly benefits is spiders and other invertebrates. A study published in 2020 compared plots invaded by M. Vimineum to plots that were not. The results of the understory arthropod community showed that plots that were invaded had seven times as many individuals along with greater species richness and diversity. The M. Vimineum indirectly benefited spider populations through changing the habitat and structure to increase prey availability.
Gallery
References
External links
NPS Plant Invaders of Mid-Atlantic Natural Areas: Japanese Stilt Grass Maine Invasive Plants: Japanese Stilt Grass , University of Maine Species Profile of Microstegium vimineum (Japanese Stilt Grass)—United States National Agricultural Library, National Invasive Species Information Center. Lists general information and resources for Japanese stilt grass Microstegium vimineum in Guide to Invasive and Hegemonic Grasses Japanese stilt grass Wisconsin DNR Japanese stiltgrass - Invasive Plants Association of Wisconsin