Beware! Japanese Stiltgrass
***Destroys biodiversity and kills natural habitat***
Japanese stiltgrass creates a thick blanket of foliage that crowds out native plant species and inhibits regeneration of our forests and fields.
Japanese stiltgrass has leafy, delicate foliage with a faint silvery vein that unevenly divides each blade. As with many invasive plants, it lulls us into complacence with its attractive greenery. But don’t be fooled! Invasive Japanese stiltgrass (Microstegium vimenium) creates a thick blanket of vegetation that crowds out native plants, destroys natural habitat, and prevents regeneration of forests and fields. It is listed as an invasive species in 23 states. And it is about to set seed.
Some areas of Franklin Park have dominant patches along the roadside or unmaintained lawns. Left uncontrolled, Japanese stiltgrass smothers out other growth. One plant can produce 1,000 seeds; and as though that’s not impressive enough, stiltgrass emits chemicals into the soil that prevents other vegetation. It’s become a big problem in Fairfax County parks, but is also found in abundance in national parks like Great Falls and the Shenandoah.
Take a close look at your yard, as it would be unusual not to have some Japanese stiltgrass growing amidst your flowers, along the driveway, or hidden under a shrub. The demands of Japanese stiltgrass are low. It will flourish in full sun to deep shade and is not picky about soil moisture. Look for it along driveways, garden beds, roadsides, ditches, and stream beds. While out and about, you might spot it on hiking trails, animal trails, edges of ponds, forest floors, and areas such as power line rights-of-way.
Japanese stiltgrass outcompeting all other native species on the forest floor.
Now is the time to take action to rid your yard of Japanese stiltgrass. Otherwise, there will be more of it next year! Established patches will become more dense and widespread. Its seed can be carried by the wind, on vehicle tires, and animal’s feet into neighbor’s yards — or parkland! It’s easy to kill Japanese stiltgrass, but can be difficult to control given its abundant seed bank when left to germinate year after year. This is why it is important to take measures now to control it, before it goes to seed. Vigilance is required, but many methods are available for removal of this plant.
A single plant of Japanese stiltgrass produces abundant foliage with a weak, shallow root system and up to 1,000 seeds that can germinate over several years.
Hand pulling is a quick and effective method for small patches since the shallow-rooted plants come easily out of the soil, but this can be labor intensive where there are larger infestations. Weed-whacking can be very effective by scalping the plant to the ground, allowing the string to sever the roots and stem (see Blue Ridge PRISM fact sheet, below, for more information).
There are also chemical measures, such as application of the appropriate herbicides for very large areas that need more aggressive control (see Blue Ridge PRISM fact sheet). Cultural/environmental methods include densely planting competitive natives such as Indian grass (Sorghastrum nutans) or White snakeroot (Ageratina altissima).
Dispose of Japanese stiltgrass with your regular trash to be landfilled. Do not compost or place in your yard waste as any seeds which may have formed may be spread to other areas.
Seemingly innocent, Japanese stiltgrass emits chemicals that inhibit growth of other plants, preventing the regeneration of our native species.
More on stiltgrass…
Unlike many invasive plants, Japanese stiltgrass was not imported as an ornamental. It is thought to have been brought to the United States as packing material inside shipping crates. Native to East Asia, it was first noticed in Tennessee in 1919. Japanese stiltgrass was established in Virginia as early as 1931. For over 90 years this invasive has had lot of time to spread throughout every county in Virginia.
Not surprisingly, deer and stormwater runoff are two of the main culprits in the success of this invasive. Deer will not eat Japanese stiltgrass, but they eat the native plants that compete with Japanese stiltgrass, and their hooves can spread the seeds across our urban forest. Stormwater runoff easily carries seed downhill, spreading it along ditches, roadsides, and stream banks.
Japanese stiltgrass gets its name from the roots that sprout from the nodes as it spreads across the ground, forming “stilts.”
Japanese stiltgrass is classified as a HIGH invasive risk on the Virginia Invasive Species Plant List from the Virginia Department of Conservation and Recreation.
For the love of our gardens, yards, urban forest, trees, parks, and wildlife, now is the time to take action against the Japanese stiltgrass your property!
More information:
Blue Ridge Prism Workshop on Japanese Stiltgrass
Fairfax County Park Authority Citizen's Guide to Non-Native Invasive ID and Control
Virginia Department of Conservation and Recreation Invasive Plants Information