How to Remove Invasive Shrubs
If your property is overrun with invasive shrubs, removing unwelcome plants is the first step in creating a beautiful garden. Join plant expert Briana Yablonski as she covers how to remove invasive shrubs.
There are many reasons you may want to remove invasive shrubs. Perhaps you’re an ecology nerd and know how they negatively impact the environment. Or maybe you want to remove a scrubby monoculture and replace it with diverse flowering perennials and shrubs. Regardless of the exact reasoning, you’re ready to learn how to remove invasive shrubs.
I get it. A few years ago, I looked out at a backyard filled with Amur honeysuckle and Chinese privet and wondered how I would ever get these plants under control. But after some research and hard work, I had a yard clear of invasives.
I’ll cover the steps involved in removing these shrubs so you end up with a landscape ready for native shrubs, a vegetable garden, or whatever else you want to plant.
Why Remove Invasive Shrubs?
If you think this process is difficult, you’re right! As you consider the time and work necessary to cut down shrubs, you may begin to wonder why you should even remove these plants in the first place.
Well, there are plenty of reasons. If you’re gazing out at a yard covered in honeysuckle or a hedge filled with winged burning bushes, you probably don’t need to hear how these plants can quickly push out other plants and overtake an area. However, if you’ve never seen invasives sprawling across acres of land, take my word when I say these plants can quickly become a serious nuisance.
As a Plant Sciences student, I enrolled in a course on invasive forest plants. Part of the class involved traveling to areas covered by these notorious plants. I remember walking through a beautiful forest dominated by trees like hemlocks and maples and dotted with smaller plants like mountain laurel, Christmas fern, and partridgeberry. However, a few minutes into our hike, the whole landscape changed.
We came upon an area covered by thousands and thousands of Japanese barberry plants. The spiky plants had created a dense understory that crowded out native plants and made walking difficult. It was dull, uninspiring, and paled compared to the native landscape. And it probably started with just one plant.
This story illustrates how invasive species can quickly multiply and conquer entire areas. They decrease diversity and beauty while choking out native plants that act as host plants for insects and food sources for birds. Some invasive plants also have shallow roots, increasing erosion and decreasing water quality.
They often outcompete native plants, so planting natives among the invasive plants won’t do much good. Instead, you should remove the invasive plants and then work to restore the area with native plants.
Before You Begin, Commit to the Long Haul
While cutting down a peony plant or pulling up a clump of hostas may be a one-hour task, this isn’t the case for invasive shrubs. These plants tend to bounce back from half-hearted removal efforts with impressive tenacity, which is part of the reason they take over native vegetation! So, to truly remove them, you must commit to the long haul.
That doesn’t mean you need to be outside each week, pulling suckers and cutting down new growth. But you’ll probably have to attack the plants more than once if you hope to remove them for good.
How to Remove
Different removal methods work well, and there’s no one-size-fits-all best approach. The plant species, the plant size, and the size of the infestation impact the ideal removal method. With that said, the following steps are a general guide.
Identify the Plant
Ensure you’re removing the right plants! Some invasive shrubs have native look-alikes, so proper identification is key.
If you’re unfamiliar with invasive plants, a good starting point is to learn the common invasive species in your area. While some plants are problems across the United States, others are known invasives in areas like the Northeast, Midwest, and Southeast. Contact your local agricultural extension or forestry office if you’re unsure whether a plant is invasive.
One way to decipher invasives from native shrubs is to look at their leaves. Invasive plants often produce leaves earlier in the spring than native shrubs and keep their foliage later into the fall.
Observe the Size of the Infestation
Removing an acre of Amur honeysuckle is a different project than removing a single plant. Therefore, observing the scale of the infestation and the size of the individual plants can help you determine the best removal methods.
If you’re lucky, you’re dealing with a single invasive shrub. Maybe a songbird dropped an Autumn olive berry into your yard, and a small seedling emerged the following year. Or perhaps the previous homeowners bought a multiflora rose plant at a nursery and planted it in their garden. Regardless of the plant’s appearance, you can often easily and successfully remove solo invasive plants using mechanical methods.
Unfortunately, many invasive plants quickly spread through seeds, rhizomes, and roots. A single Japanese barberry or Chinese privet plant can multiply into 20 or 50 plants within a few years. Large numbers of plants take more time to remove, but choosing the proper removal methods can make the task more manageable.
Start with Mildly Impacted Areas
If you’re dealing with hundreds of square feet or acres of property, plan your attack strategy before starting the removal process. Start with the edges of the infestation rather than the middle.
Controlling plants at the edges will slow the spread of invasive plants into uninfected areas. Once the edges are under control, you can remove plants near the densely impacted interior.
Wait Until the Proper Time of the Year
You can remove invasive shrubs at any time, but late fall through early spring are the best times for removal. Growth is limited during this time, making working through vegetation and reaching the targeted invasive plants easier.
Since deciduous plants drop their leaves in the late fall, properly identifying invasive plants is more difficult in the winter. However, it’s still possible to properly identify via bark, fruit, and plant forms. And you can always ID plants in the summer and mark them for control later in the year.
Another option is to wait until the early spring. Since invasives like Amur honeysuckle and Chinese privet leaf out earlier than native shrubs, it’s easy to ID them. However, the lack of native plant growth means you can still easily navigate your garden, woodlot, or hedge.
Start with Mechanical Control Methods
Mechanical methods like pulling, cutting, and digging can help you remove many invasive shrubs. Since mechanical removal methods don’t cause much harm to the surrounding environment, they’re often the first line of attack.
Use your hands to pull out small shrubs while removing as much of the root system as possible. Pulling plants from moist soil is easier, so wait until after it rains.
Pulling larger shrubs from the ground is difficult, but you can still remove them using mechanical methods. Use sharp bypass shears or a handsaw to cut the shrub a few inches above the ground. Many shrubs will resprout after you cut them, but cutting back vegetation will slow growth and prevent seed production.
Determine Your Thoughts on Chemical Control
While mechanical control methods can thoroughly remove small and single plants, clearing an entire backyard filled with invasives can take weeks or months. And many of these shrubs will regrow after you cut them.
Although I generally avoid spraying herbicides, I’m not against using them to control invasive shrubs. Sure, I can easily and effectively remove garden dandelions and pigweed by hand. But a yard filled with autumn olive and privet? Well, that’s no match for me.
Many plant ecologists and wildlife biologists share my sentiments and believe the minimal harm caused by a single herbicide application is better than the damage caused by leaving these shrubs intact. Utilizing herbicides leads to more effective removal than mechanical control alone. Ultimately, deciding how you feel about using herbicides on your property is up to you.
Choose the Proper Chemical Control Method
If you choose to use herbicides, the next step is choosing the safest and most effective method. Whatever you do, don’t just grab a generic herbicide and start spraying your shrubs. Not only is this not the most effective method, but it can also damage or kill desirable native plants and lead herbicides to enter the soil and water.
Instead, you should choose between two widely accepted methods: painting cut stumps and spraying regrowth. I’ll explain these two methods below.
Cut Stump Method
The cut stump method, also known as cut and dab, involves cutting invasive shrubs a few inches above the ground and immediately painting the stump with an herbicide. The herbicide travels throughout the plant and leads to its death. When done correctly, this method can lead to a success rate of over 90%.
Late fall is the best time for cut stump treatment, but spring and winter will also work well. Regardless of the time of year, ensure no rain is forecasted for the following few days. Rain can wash off the herbicide and limit its effectiveness.
Before you begin, select a proper herbicide and read all the product warnings and application instructions. Glyphosate and triclopyr are two herbicides commonly used for the cut stump method. Overly diluted products will not work effectively for cut stump treatments, so choose a product with 20% glyphosate or 10% triclopyr.
While both products are effective controls, the best herbicide for the job varies between species. If you’re removing plants in a wetland or area with a high water table, choose the aquatic formulations of these products.
Once you’ve selected your herbicide, cut the shrub’s stem an inch or two above the ground and paint or dab the stump with a systemic herbicide. Your goal is to thoroughly cover the cut side without creating herbicide runoff.
If you’re removing only a few plants, you can cut the stump and immediately apply the herbicide. However, a team of two works well on a larger scale. One person can cut the shrubs, and the second can come behind them with an herbicide. I also recommend using dyed herbicides at larger scales since they allow you to keep track of what plants you’ve treated.
Spray Regrowth Method
An alternative chemical control method involves cutting shrubs, letting them regrow, and then spraying the regrowth. This method is best reserved for shrubs with many small stems, like Japanese barberry and multiflora rose. It’s also a suitable method if you don’t have access to the concentrated herbicides required for the cut stump method.
First, cut the stems at an inch or two above the ground. You can do this any time of year, but it’s easiest to access plants during the late fall through early spring. Wait until the cut stumps send out new growth, then spray the growth with herbicide.
As with the cut stump method, people commonly use glyphosate or triclopyr for spraying foliage. However, you should dilute the product until it contains 1-2% of the active ingredient.
A backpack sprayer is the easiest way to spray the herbicides. Fill the sprayer with the product and spray the foliage until moist but not dripping wet. Be careful not to spray surrounding vegetation since the herbicides will kill plants they contact.
Monitor for Regrowth
Regardless of which removal method you use, the shrubs may regrow. Look for regrowing plants and new seedlings, and remove them as soon as you spot them. Remember, removing a few small seedlings is easier than a yard full of shrubs!
Replanting with Native Species
Once removal is complete, it’s time to replant the area with native species. Ensure you’ve removed all invasive plants in the area because even a single plant can outcompete native plants.
Adding native plants will prevent soil erosion, provide food for wildlife, and add beauty to your lawn. Alternatively, you can plant ornamental but non-invasive plants.
Removing invasive shrubs allows you to prevent the spread of these plants and reclaim natural and ornamental areas. Once the invasive plants are gone, you can create a yard or garden that suits your desires.