How to Get Rid of Common Buckthorn
Did you find common buckthorn growing in your yard or near your garden and just want it gone? It can take several years to properly eradicate this plant from your yard, depending on how dense it is. In this article, certified master gardener Liz Jaros shares her top tips for removing common buckthorn from your yard or garden.
An understory plant that has dense, dark foliage, and an extra-long growing season, buckthorn is currently one of the most dangerous and invasive threats to our forests, wetlands, and prairies. With the ability to outcompete native understory plants for nutrients and moisture, and the tendency to spread like wildfire, buckthorn has fast become a major landscape foe. But it wasn’t always that way.
When settlers first introduced buckthorn to America in the 1800s, it gained fast popularity as a privacy hedge. Fast forward 200 years, and the plant has become a major headache in temperate zones worldwide.
Buckthorn is quickly colonizing near the forest’s edge, degrading wildlife habits and crowding out plants that control shoreline erosion. And a major effort is underway to eradicate it.
As gardeners, we have a big role to play in that process. Buckthorn has made its way into rural and urban settings and continues spreading rapidly. As we work the earth in various ways, we should always be on the lookout for this invasive perennial plant and commit to its removal. Let’s take a closer look at this landscape menace and discuss some ways to get rid of it.
Identifying Invasive Buckthorn
The first step in getting rid of buckthorn is making sure you can identify it apart from native species that are beneficial to the environment. Both mature buckthorn trees and young saplings can be identified through their berry clusters, leaves, flowers, and tree bark.
Mature buckthorn can resemble a multi-branched shrub or a small tree, with heights of up to 25 feet and trunk girths of up to 10 inches. Young saplings can resemble a groundcover, a common weed, or a small shrub. So identification is not always easy.
There are two species of invasive buckthorn, Common and Glossy. While there are a few key similarities, there are also some differences between the two equally invasive species.
Common Buckthorn (Rhamnus cathartica)
One of the first deciduous shrubs to leaf out in early spring and one of the last to lose its leaves in early winter, common buckthorn is easiest to identify at those two times of the year.
Thriving in dappled sun locations with well-drained soil, this plant is often found in woodlands, roadsides, and untended landscapes.
The leaves on common buckthorn are oval and dark green, with finely toothed edges and 3-5 curved veins on each side of the midrib. They extend from either opposite or sub-opposite leaf axils, which means they pretty much grow in pairs along the stem.
The flowers on common buckthorn are small and green-yellow, with four petals that bloom in May. Fruit appears soon after in clusters of green pea-sized ‘drupes’ that eventually turn black and cling to branches long into the winter.
Common buckthorn will have gray to light brown bark with raised bumps or lenticels all over the exterior and sharp thorns. One of the most memorable ways to identify it is to look for a pair of buds at the terminal branch ends that resembles a buck’s hoof.
Glossy Buckthorn (Frangula alnus)
Slightly shorter and more rounded in form than common buckthorn, glossy buckthorn prefers wet soil and can usually be found in marshes, bogs, riverbanks, and wetlands.
Similar to common buckthorn, glossy buckthorn also has dark berries that grow in clusters. There are differences to take note of to identify it as glossy buckthorn, though treatment won’t change between the two.
The leaves on glossy buckthorn are also opposite to sub-opposite, oval, and dark green but have a more dense concentration of veins. Look for 8-9 curved lines on each side of the midrib to indicate glossy rather than common buckthorn. It can grow in both shade and sun, which makes it extra prolific.
Glossy buckthorn flowers are similar to those of common buckthorn, but they are a creamier yellow color and have five petals. They also bloom slightly later than their common buckthorn cousins.
Trunks and branches also have lenticels, or raised spots, and a bark that is often mistaken for cherry or lilac wood, but they do not have thorns. If you scratch the surface away with a knife, you’ll see sapwood and heartwood that’s orange-yellow to pink in color.
How Buckthorn Spreads
One trait that makes buckthorn so difficult to eliminate is how easily it can spread. It has exceptional reproductive and regenerative characteristics that help it to survive, even when we don’t want it to. Buckthorn spreads easily in two different ways:
Suckers or Wild Shoots
Buckthorn produces suckers or wild shoots that sprout from root clumps below ground. Each sprout then becomes a new plant, and the colony expands to take over whole masses of land if left unchecked.
This is buckthorn’s most menacing characteristic. Not only do its long-lasting berries drop to the soil and self-seed, but birds and mammals consume them as a food source and can travel great distances before depositing seeds in other locations. These seeds can remain viable for up to five years.
Virtually unchecked in the wild by disease or pests, buckthorn has no natural predators and serves as a host to other plants’ enemies, like crown rust fungus and soybean aphids.
And although common buckthorn thrives in part shade while glossy buckthorn prefers full sun, each has demonstrated the ability to grow and spread in both low and high-light locations.
Since it has a longer active growing season than any other deciduous plant in the landscape and creates a lot of shade, it can easily outcompete other native species for light, moisture, and nutrients, including those that hold soil in place to prevent erosion on the forest floor and at the water’s edge.
How to Get Rid of Buckthorn
While there is no way to completely annihilate buckthorn, you can undertake several manual, biological, and chemical actions to keep populations in check. Let’s review each one so you can decide which to try first.
Getting rid of buckthorn manually is fairly straightforward. The method you use will depend on the size of the stems. Smaller stems (about 1″ in diameter or less than 2″) can be done by hand most of the time. Larger stems (bigger than 1-2″ diameter) will require some tools. The primary goal is to prevent seed production, spread, and resprouting.
Once you’ve identified this invasive plant in your landscape, be ready to attack it in the fall. The leaves on buckthorns stay green longer than most trees, so they will be easier to spot in the early autumn months.
Learn how to identify these plants, confirm that they are indeed common or glossy buckthorn, and head outside with your garden tools.
Seedlings or Small Shrubs
Small seedlings with a 3/8-1″ diameter may be pulled by hand if they are young enough. The soil should be moist, and only a small population to use this method. If they are slightly larger or there is any resistance, use a shovel or weeding instrument such as a Weed Wrench or Root Talon. You want to make sure you’re removing the roots and not just the tissue that’s above the ground.
A slow and steady pull should do the trick. You want to disturb the soil as little as possible. Disturbing the soil can aid in seed germination. Shake out the dirt from the roots, but do not allow them to contact the soil again. Press down on the soil once the young plant has been removed.
Mature Shrubs or Trees
For larger trees or shrubs, you’ll have to cut them down and try to prevent new growth. Use an axe, saw, or lopper to cut them as close to the ground as possible. The stump should be treated within 30 minutes with herbicide or suffocated with a plastic bag for up to two years. If the stump is not treated or suffocated, there will be numerous sprouts coming from the stump next season.
Image Credit: “Cut stump of common buckthorn” by Eli Sagor, CC BY-NC 2.0, via Flickr. Cropped. (Image Use Allowed With Attribution)
Though there are not any natural predators of buckthorn, you can call in a herd of goats to graze on this noxious weed. It will take a few munching sessions, but there are many benefits to using this method.
No chemicals are used, so this is a completely eco-friendly method. The goats have tough stomachs that can handle buckthorn without getting sick. And lastly, goat droppings fertilize the soil, leaving it better than it was when they arrived. Plus, you get to have a herd of cute goats in your yard for an afternoon!
Using chemicals should be a last resort when getting rid of buckthorn. They are harmful to the environment and could possibly contaminate the area. It can also cause the soil to become infertile. Try other natural methods before taking the drastic measure of using chemicals.
Both buckthorn varieties can be treated with chemicals to a certain extent. For best results, chemical applications should be performed when plants have fully leafed out and are actively photosynthesizing.
This will help draw poisons down toward plant roots and disperse them throughout the vascular system.
Using a product that contains glyphosate or triclopyr, small plants can be treated with a foliar spray that will hopefully cause systemic damage.
For larger shrubs, applications should be made directly to freshly cut stumps by painting or dabbing chemicals directly onto the exposed wood. Follow the manufacturer’s directions carefully and be mindful of nearby plants that could be negatively affected.
Additional Removal Tips
Now that we’ve reviewed how to get rid of buckthorn, here are a few more tips to ensure it doesn’t return. Buckthorn can be a very relentless plant, so it may take a few attempts to remove it completely. However, there are some ways to keep that from happening.
Because buckthorn is so determined to take over, it is very important that you dispose of the plant and all of its debris in a way that will prevent it from coming back. Do not toss it into your compost or put it in your natural debris pile. This can cause problems for other gardeners.
Promptly remove debris and burn or dispose of plant parts as cleanly as possible. You can place it in plastic bags and seal them tightly. Follow this action by covering stumps with black plastic or a tin can and leaving it in place for two years.
Follow Up on Treatment
Since buckthorn seeds can remain viable in the ground for up to five years, it is important to follow up next season with additional treatment. Carefully inspect the areas you’ve gotten rid of buckthorn to see if any new growth has appeared.
Continue to pay attention to the areas you clean up over the next few years, and pull up any baby buckthorn shrubs you see sprouting up. Repeat this for a few seasons until you no longer see any buckthorn growth.
Proper Garden Care
Thankfully, when an area is properly cared for and mowed, buckthorn is less likely to spread. It is important to be very thorough when using a lawn mower. Be sure to get as close to the ground as possible.
Even if you do not think the area is in need of a mow, run the mower or weed whacker over it. This ensures a lower chance of buckthorn returning or invading in the first place. Also, take extra care in disposing of any clippings.
Stubborn buckthorn can take a few seasons to get rid of. It can be tiring, and you may feel like giving up! Expect to see buckthorn spreading in your yard or garden as long as you are letting it grow there. But don’t let it get to that point! Act fast and keep following up.
Try one of the above methods for getting rid of buckthorn and keep at it. Practice patience here! Persist through the next few seasons, and soon enough, you’ll be able to enjoy a buckthorn-free garden.
Awareness and word of mouth are important weapons in the eradication of buckthorn. Take what you’ve learned from this article and talk to your neighbors. Share your new knowledge on garden forums and through local green groups.
If we can get everyone on board and actively working against the spread of common buckthorn, we can make some progress toward getting rid of it.
The effort can also be aided by intentionally planting species that hold their own against buckthorn. Gray dogwood, sumac, elderberry, and bladdernut are all native plants with fast-spreading habits that are not as destructive as buckthorns.
They share many of the same cultural requirements and can be worked into the landscape to compete with invasive colonies and help crowd them out.
Once you’ve discovered common or glossy buckthorn in your landscape, you can expect it to keep popping up here and there. That’s just the ugly truth about this invasive species. But with diligent maintenance and a commitment to keeping it in check, you can stop it from taking over your property and prevent it from spreading to others.