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.
Perhaps you think this leafy, delicate foliage with a faint silvery vein down the middle is an attractive grass, 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 smothering the forest floor in our own local parks, including Great Falls Park and Shenandoah National Park. It is found throughout our Franklin Park & Franklin Forest neighborhood, and it is about to set seed!
Japanese stiltgrass outcompeting all other native species on the forest floor.
Now is the time to apply control measures. Otherwise, next year it will be more dense and widespread, and our parks and natural areas will be even more compromised. A single plant can produce up to 1,000 seeds, making this a fast spreader from Florida to New England and as far west as Texas. It is listed as an invasive species in 23 states.
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, stream beds, hiking trails, animal trails, edges of ponds, forest floors, and areas such as powerline rights-of-way.
While it’s easy to kill Japanese stiltgrass, it is difficult to control given its abundant seed bank when left to germinate year after year. This is why it is important to attack small patches before it becomes quickly established. 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.
It is important to remove this plant before it sets seed, which in the DMV is approximately August 10. Although it can be labor intensive in larger areas, hand pulling is a quick and effective method for small patches as the shallow-rooted plants come easily out of the soil. Weed-whacking can be very effective by scalping the plant to the ground, allowing the string to sever the roots and stem.
Cultural/environmental methods include densely planting competitive natives such as Indian grass (Sorghastrum nutans) or White snakeroot (Ageratina altissima). There are also chemical measures, such as application of the appropriate herbicides in accordance with label instructions (remember, “the label is the law!”).
Do NOT compost Japanese stiltgrass and do NOT put it into your yard waste bins!
Seemingly innocent, Japanese stiltgrass emits chemicals that inhibit growth of other plants, preventing the regeneration of our native species.
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 beastly 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 the forest floor. 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 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