Photographer: Chris Evans Affiliation: Illinois Wildlife Action Plan Source: Bugwood.org Copyright: (CC BY-NC 3.0)
Photographer: Chuck Bargeron Affiliation: University of Georgia Source: Bugwood.org Copyright: (CC BY 3.0)
Microstegium vimineum is a sprawling understory grass that germinates in the spring and grows throughout the summer. It grows to heights of 2 to 3.5 ft. The leaves are tapered at each end, pale green and 1-3 in. long. Tiny flowers are produced in late summer to early autumn, and looks like a spike-like panicle. Florets on the panicles can be cross-pollinated (chasmogamous) or self-pollinated (cleistogamous). Small yellow reddish seeds ripen from September to November.
Japanese stiltgrass can create dense, monotypic stands (pictured right).
It grows more slowly in un-disturbed areas. However, in disturbed areas it can shade out other native ground cover in 3-5 years. By changing the forest understory habitat, it negatively affects ground-nesting birds; specifically, the nesting habitat of the Bobwhite Quail. Additionally, it provides good habitat for predators of ground-nesting birds, such as snakes. Since white-tailed deer selectively feed on native grasses and not Microstegium vimineum they are reducing competition and encouraging the spread of this invasive grass; making this grass a serious threat to forest understory fauna and flora.
Microstegium vimineum is an annual grass that reproduces both sexually and asexually. This grass is a colonial species that spreads by seeds and stem nodes. One plant may produce 100-1,000 seeds that may be dispersed by water flow during heavy rains, and can be contaminants of hail, soil or potted plants. Animals like deer and other grazers reportedly do not browse it, but they inadvertently spread the seeds. Seeds remain viable in the soil for seven years or more, and can survive 10 weeks submerged in water (ie: after a flooding event). Seeds germinate in the spring, and seedlings grow during the summer. The grass is adapted for low-light conditions; meaning it can photosynthesize is constantly shaded areas but it is also found in open/sunny areas.
This grass was first collected in Tennessee in 1919 and spread rapidly. By 1960, it was present in several Midwestern, Southeastern and Atlantic states. Porcelain shipments from Asia usually use this plant as a packing material, and probably the means for its introduction into the United States.
Japan, Korea, China, Malaysia and India
U.S. Habitat: Prefers shady, moist locations and is commonly found in in swamps, floodplains, woodlands near streams and forested wetlands. It easily invades areas that are regularly mowed, tilled or any action that causes a soil disturbance.
U.S. Present: AL, AR, CT, DC, DE, FL, GA, IL, IN, KY, LA, MA, MD, MO, MS, NC, NJ, NY, OH, PA, SC, TN, TX, VA, WV
Prevention of Microstegium vimineum introduction is the top management strategy. Thankfully, because it is an annual with shallow roots, hand removal is possible. Studies have shown that combined management strategies work best. Hand-weeding and post-emergent herbicides work best at removing Japanese stiltgrass, and increasing resident plant community productivity. The rehabilitation of native plant communities is essential when managing Japanese stiltgrass because of the animals that rely on native understory plants. Even though grazers do not browse on this grass recent evidence has shown that native insects will consume it. In its native range, M. vimineum is host to twelve plant pathogens. In 2009 in West Virginia, it was found to be infected with Bipolaris group of fungi. The infected Japanese stiltgrasses quickly spread the fungi amongst its population, causing delayed seed production and eventual die-off. This pathogen did not seem to spread to other plants and affected M. vimineum directly, making this a potential biological control that with help treat areas that are too large for hand weeding. Further research into biological controls is continuing.
Barden, L. S. 1987. Invasion of Microstegium vimineum (Poaceae), an exotic, annual, shade-tolerant, C4 grass, into a North Carolina floodplain. American Midland Naturalist, 40-45.
Bradford, M. A., Devore, J. L., Maerz, J. C., McHugh, J. V., Smith, C. L., and Strickland, M. S. 2009. Native, insect herbivore communities derive a significant proportion of their carbon from a widespread invader of forest understories. Biol. Invasions.
Flory, S. L. 2010. Management of Microstegium vimineum invasions and recovery of resident plant communities. Restoration Ecology, 18(1):103-112.
Gibson, D. J., Spyreas, G., & Benedict, J. 2002. Life history of Microstegium vimineum (Poaceae), an invasive grass in southern Illinois. Journal of the Torrey Botanical Society, 207-219.
Kleczewski, N. M., & Flory, S. L. 2010. Leaf Blight Disease on the Invasive Grass Microstegium vimineum Caused by a Bipolaris sp. Plant disease, 94(7):807-811.
Woodward, Susan L., and Joyce Ann. Quinn. 2011. Japanese Stilt Grass. Encyclopedia of Invasive Species: From Africanized Honey Bees to Zebra Mussels. Santa Barbara, CA: Greenwood. 466-69. Print.