Once the leaves have fallen, you might notice a “green haze” in the understory of our forests. This time of year is a great chance to notice where invasive exotic plants, which often hold onto their leaves longer than our native species, are located. In Chittenden County, invasive exotic plants are present on most properties, at levels ranging from a few seedlings scattered throughout a large woodlot to buckthorn and honeysuckle monocultures dominating dozens of acres.
I cannot overemphasize what a serious threat invasive exotic plants (I’ll just call them “invasives”) pose to the health of our forests. These species disrupt the natural process of regeneration in the forest by outcompeting our native trees and plants. Many invasives are allelopathic (secreting chemicals into the soil that inhibit the growth of other species), prolific seed producers and able to sprout prolifically after being cut or pulled, even from a tiny fragment of root or stem.
We will never get rid of invasives. As a result, instead of “eradication” we now talk about “control.” We can get to an acceptable level of “control” by decreasing populations of invasives to the extent that you can easily hand-pull new sprouts without needing to take more drastic measures.
We all live busy, full lives, and so it is critical that woodlot owners, in addition to considering what treatment methods are effective, are realistic about how much time and effort they can commit to invasive species removal — this will influence the control strategy you ultimately adopt. On my woodlot, about 30 acres were heavily infested with invasives — mostly barberry, honeysuckle, and multiflora rose. After a lot of pulling and digging, it became clear that I didn’t have the time to make a difference using these methods; I needed to be a realist and recognize the need to take a different approach.
With a few small invasive plants or a very small area (like a yard), you may be able to “hand-pull” (pulling the plant and its roots up) or cut them repeatedly. However, these “mechanical” approaches don’t work on even moderate-sized infestations; because of invasives’ ability to sprout, you may need to cut or hand-pull several times a year for several years before you achieve any measure of control (especially with cutting). If you can’t commit to this, this is not the option for you.
Herbicide shouldn’t be our first resort, but it is by far the fastest, cheapest, and most effective method of controlling invasive plants. If you have an infestation of small plants with some that are too big to pull out, I recommend a hybrid approach, hand-pulling what you can and stump-treating plants that are too big to pull. “Cut-stump” application of herbicide is targeted, effective and virtually eliminates any impact to non-target plants. Tractor Supply offers products with the active ingredient glyphosate (41%) for $25-50/gallon. On my land, I cut invasives with a folding hand-saw and use an applicator called a “Buckthorn Blaster,” ($5) to apply herbicide neatly and efficiently to the surface of a stump. This method will save you years of repeated cutting.
Large, heavily infested areas cannot realistically be controlled by mechanical means, or even by the “hybrid” approach. In these cases, herbicide application using cut-stump application and foliar spraying (spraying the leaves of the plant) may be warranted. If this is the case on your land, you can either hire an invasive species control company, or, if you have the time and the desire, you can do it yourself. On my land, I use a hand-pumped backpack sprayer ($50-80) for foliar applications. To do this, you must first learn how to safely apply herbicide — landowners can legally apply some herbicides on their own land, but I’d recommend signing up for the Agency of Agriculture Food and Market’s day-long Certified Pesticide Applicator course. It’s also critical that you are confident identifying invasive plants — VTInvasives.org can get you started on that.
No matter how we do it, the most important thing is that we control these invasive exotic plants, allowing our forested ecosystems to grow healthy trees, plants and wildlife. Understanding the steps necessary to realistically deal with the infestation you have, and the tools at your disposal, is the key to getting to an acceptable level of “control.”
For more information on invasive species and their control, visit VTInvasives.org.
Ethan Tapper is the Chittenden County forester. He can be reached at firstname.lastname@example.org, 585-9099 or at his office at 111 West St., Essex Jct.