Let’s talk about how we can control and manage invasive plants like Japanese Stiltgrass.
Invasive plants don’t seem like a big deal until you walk through your meadow one day and that is all you can see….they have taken over and killed off the other healthy native plants that you wanted to thrive on your property.
Invasive species can really hurt your efforts to keep your land natural and thriving for native plants and animals.
What is Japanese Stiltgrass?
Japanese Stiltgrass (microstegium vimineum) is an invasive species which poses a threat to any woodlot in which it establishes. It is an aggressive spreading annual plant which produces 100-1000 seeds per plant and can quickly dominate native species in the affected area.
Japanese Stiltgrass poses a major problem for property owners.
According to numerous sources, Japanese Stiltgrass was introduced in the United States early in the 20th Century from Asia. The species was used as a packing material for various products imported from Asia and the assumption is it began to get established.
Since then, it has spread across the eastern US affecting yards, meadows and wood lots as it goes.
Why is Japanese Stiltgrass a Problem?
While Japanese Stiltgrass is not the first invasive species we have faced on our property, Autumn Olive has that honor, it is by far the hardest to control in my opinion.
Japanese Stiltgrass poses a problem due to its ability to produce hundreds of seeds per plant each fall, then those seeds germinate next spring or remain in the soil for up to 7 years.
Which means a property owner can eliminate all the plants this summer and then have Japanese Stiltgrass back again next spring! ARGH!!
It can grow in full sun or shade and is very tolerant of most soil conditions. And once established, Japanese Stiltgrass has the ability to dominate the landscape by out-competing native vegetation.
Once well established it can also start to affect tree growth by changing the soil nutrient and mineral composition. Boo! Hiss!
Then along comes fall and winter and you get this….
In the fall, as the plant goes dormant, it creates a mat-like cover everywhere it grew.
This leads to another issue with stiltgrass as it can limit spring green up for plants that need sunlight to grow and this allows the stiltgrass to re-establish first.
How to control Invasive Species like Japanese Stiltgrass
I mentioned Autumn Olive earlier in the post and how it was the first invasive we dealt with. Autumn Olive is a bush, although it can really get going if left unchecked, it is easier to identify, cut and remove.
Japanese Stiltgrass requires a much more persistent and aggressive approach as it grows in large patches and spreads easily.
A land owner has to stay focused to get rid of stiltgrass and remain so for several years until the seed bank is exhausted and additional sources are removed.
In our case, a recent logging operation disturbed the soil and exposed the seeds allowing them to grow.
Our neighbors have Stiltgrass and it is likely the source of the seed bank on our property. Just about everywhere the forest floor was dug up in some way, either by falling a tree or skidding a log, Japanese Stiltgrass has grown.
3 Ways to Control Japanese Stiltgrass
Last fall I experimented with three types of control in the August-September time frame, just before the plants seeded out:
- Hand pulling
- Herbicide control
- Controlled burning/mowing/trimming
All three removed the plants that were present.
Hand-pulling and controlled burning/mowing allowed for native plant regeneration with some regeneration of stiltgrass, but the stiltgrass did not make it to seed.
The most effective, but also the most damaging to all plants was herbicide control.
The herbicide selected was glyphosate (used in Round-up) which is a non-selective herbicide ( it kills just about everything green it touches). Regeneration of native plants and stiltgrass was very slow in these areas.
Going Forward with Controlling Invasive Plants
This spring I am taking a multi-pronged approach.
It is now late April and the stiltgrass is around 2 inches tall. I am treating several acres with an herbicide called imazapic which has shown to work in controlling stiltgrass and not clearing all the native vegetation.
Those plants not controlled with my initial application will receive spot spraying of glyphosate in the June/July time frame followed by weed eating and hand-pulling of remaining plants before seedout.
I am anticipating this approach will require 3-5 years to control and remove Japanese Stiltgrass on our property where I estimate I have nearly 4 acres of stiltgrass.
Preventing Japanese Stiltgrass from Spreading On Your Property
The best approach to controlling the species is not to introduce to your property in the first place.
If your neighbor’s property has stiltgrass on it and near your boundaries, it is likely already too late.
If you begin operations of any kind that will disturb the soil, it will begin to grow. If this is the case, start now with the control and try not to let it seedout this fall.
If your neighbors land is clear of stiltgrass and you are planning on logging the property or doing some other earth moving or building – ensure your contractors pressure wash their equipment prior to starting work on your land.
Many contractors pressure wash and clean their equipment between jobs to prevent the spread of invasive species, but just to be safe, ask them before they begin.