Japanese Stilt Grass
Microstegium vimineum
How did it get here?
First
identified in Knoxville, Tennessee in 1919, this grass
may have been introduced accidentally through its use
as a packing material for Chinese porcelain. Its native
range is Japan, Korea, China, Malaysia, and India. Japanese
stilt grass was found in western North Carolina in 1933.
How to spot
Microstegium
vimineum grows in a sprawling pattern and may form
colonies to 3 feet in height. It has a branched stalk
with alternate
leaves that are thin, pale green, lance-shaped, and
about 3 inches long. The leaves have a silvery strip of
reflective hairs in the center of the upper surface. Delicate
spikes of flowers appear near the tips of the stalks in
late summer and early fall.
Habitat characteristics
- Moderate to dense shade.
- Moist, nitrogen-rich soils with acidic to neutral pH.
- Naturally or artificially disturbed sites such as roadsides, ditches, woodland borders, floodplains, and streamsides.
- Selectively colonizes bare ground not occupied by other plants.
Life cycle
Japanese
stilt grass is an annual
that reproduces from seed. The grass grows in colonies,
rooting from the nodes and sometimes forming dense stands
of the same plant. Each plant produces as many as 1,000
seeds that remain viable in the soil for at least five
years. Seeds are dispersed naturally by wind and water
(streams and ditches) and are transported by humans in
hay and soil.
Look-alikes and how to distinguish
- Cutgrass (Leersia virginica)—longer leaves.
- Knotweed (Polygonum persicaria)—pale to dark-pink calyx and glossy, brown nutlets.
Why is this plant a problem?
Although
it is generally slow to colonize undisturbed areas, Japanese
stilt grass can rapidly fill disturbed areas such as streamsides
scoured by flooding and sewer line rights-of-way that
are mown annually. The dense stands that it forms can
crowd out native vegetation in just a few years. Once
these stands are established, the natural soil conditions
such as pH and organic composition begin to change, potentially
preventing the re-establishment of the original native
species. Deer do not eat Japanese stilt grass, giving
the plant an advantage in heavily grazed locations.
Management approaches
- Avoid disturbing vegetation and soil in areas free of this grass.
- Control new infestations early to prevent establishment. Seed will persist in soil for many years.
- Pull by hand (in small areas) or use a mower or powered
weeder (in large areas) when plant is in peak bloom
but before it produces seeds. This occurs in late summer
in the Southeast. If plants are pulled too early, additional
seeds in soil will have time to germinate and replace
the stand. Dislodge shallow roots completely, as plants
break off easily.
Other resources
WEB
Plant Conservation Alliance, Alien Plant Working Group
Southern Appalachian Man and the Biosphere
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