Introduced in 1919 in packing material from China and starting in Tennessee, Japanese Stiltgrass, Microstegium vimineum, has rapidly spread across the eastern United States and as far west as Texas, and become a menace to native plants. Spreading from seeds that can remain viable for 5- 7 years, stiltgrass can appear in lawns, ground covers, and planting beds and spread with amazing speed. Each plant can produce up to 1,000 seeds annually, so if you have a small invasion of stiltgrass one year, you know you will have loads more next season if you don’t eradicate it.
Stiltgrass is more than just a nuisance — it reduces biodiversity. In heavily infested areas, native forbs simply can’t compete. They’re quickly overrun, disappearing under the dense growth. Deer and rabbits won’t eat it, so it thrives unchecked, spreading across woodlands like a green carpet. On my nearby hikes on the rail trail in August, it covers the understory as far as the eye can see.
Here in the mid-Atlantic, August is peak stiltgrass season. By mid-July, I start spotting the first slender stalks in my flower beds. That’s the moment to act — pull them before they seed. If you wait, you’ll be facing a much bigger problem in just a few weeks, and you might lose the battle entirely. Early and persistent eradication is key.
The easiest and most effective way to control stiltgrass is by hand weeding. I manage a property where it has invaded a liriope ground cover — tricky, since liriope also looks like grass. Timing is everything. I wait until the stiltgrass has grown taller than the liriope, so I can grab it above the liriope blades, but before it sets seed. I pull it out by the handful, making sure to get the shallow roots, which come out easily, especially when the soil is moist.
Stiltgrass can get three feet tall but usually lays down so it looks much shorter and can completely carpet the ground. Chemical herbicides can be used and will work but be careful of the vegetation that is growing amongst or nearby the stiltgrass as that can be burned
Stiltgrass is an annual so the first cold spell or frost will kill it. You might think that will take care of it, but wait for next year. All those seeds remain viable and the infestation will be much worse.
When removing stiltgrass, always bag it and dispose of it with your yard waste — never put it in your compost pile, or you may end up spreading stiltgrass seeds into your garden.
This is a great YouTube about stiltgrass – how to identify and eradicate.
Yikes! That is scary. Apparently, it’s relatively new here in Wisconsin, but I’ll check and see where it’s spread. So many invasives…
I found your breakdown of tackling Japanese stiltgrass truly eye-opening, especially the tips on hand-weeding before seed set and never composting it. That persistence really matters when you’re trying to protect native plants.For anyone working on similar invasive species or climate-specific landscaping challenges, Ventana Outdoor Living offers some great examples of desert-friendly designs that balance beauty with resilience https://ventanaoutdoor.com/best-drought-resistant-plants/ . Whether you’re dealing with invasive ground covers or designing around water constraints, intentional choices make all the difference. Thanks for the great insights, it’s a powerful reminder that early, steady efforts yield real rewards in garden health.
Since it is seed-free until autumn, why not compost it? It breaks down slowly, great for smothering wavyleaf basketgrass or for wadding under logs to prevent erosion in problem runoff areas.
Possibly, but I wouldn’t want to chance having any viable seeds attached. The growth habit of some might be more advanced. I suppose if you are very careful, you could.