Buckthorn is shorthand for the genus Rhamnus, which includes about 110 species of shrubs and small trees. Unfortunately, that makes it pretty difficult to identify “Buckthorn” in general.
Which Buckthorns Are Invasive and How Do I Identify Them?
Buckthorn species are native to North America, South America, Asia, and Europe – so why are they considered to be an invasive species in much of the midwestern U.S.?
As a brief reminder, an invasive species is a species of plant (or animal or fungi) that causes ecological or economic harm in a new environment where it is not native (NOAA’s definition).
Because the term “Buckthorn” encompasses over 100 species of plants, it’s possible for one species of Buckthorn to be totally native and non-problematic in an area while another species of Buckthorn is invasive and problematic. The confusion arises from our language more than anything!
The common name for the problematic Buckthorn species is “European Buckthorn,” but again this term seems to include several different species.
In much of the U.S., the most invasive forms of Buckthorn are:
- Common Buckthorn (Rhamnus cathartica).This species is a problem across the Northeastern, Midwestern, and Western U.S. It was introduced in the 1800s as a garden plant. It is a tall shrub, with multiple stems that grow up to 20 feet tall. The leaves are roughly elliptical with small teeth and a pointed tip. They are dark green and slightly glossy.
- Glossy Buckthorn (Frangula alnus). This species is cultivated in three different forms: a tall and narrow form, and two forms with narrow and fernlike leaves. This species is particularly aggressive in wetlands. This species otherwise is broadly similar appearance-wise to the Common Buckthorn.
It is illegal to import, sell, or cultivate these species in some states.
Collectively, we’ll follow the rest of the non-scientific community and call these species European Buckthorn.
Before removing or killing European Buckthorn, make sure you’ve got the right plant. It’s easy to confuse European Buckthorn with cherries or chokecherries. The cherry and chokecherry trees generally have longer leaves with a more pronounced point. The easiest way to tell the difference is with the buds.
The buds (brand new leaf growths) of European Buckthorn look like goat hooves, sometimes with a short thorn between two buds. They are close together and nearly cross. The buds of the chokecherries and cherries grow alone rather than in pairs.
Why Is European Buckthorn So Bad?
European Buckthorn is bad news for the forests and other ecosystems of the U.S. When it invades, it out-competes native plants for light and nutrients. When European Buckthorn starts dominating an ecosystem, it doesn’t leave much food for the native animals to eat.
All this means that a European Buckthorn invasion threatens the wellbeing of the ecosystem. Even worse, European Buckthorn tends to degrade the ecosystem further by shading out native plants. This contributes to erosion, causing hills to slump or even collapse. Finally, European Buckthorn harbors fungi and insects that are damaging to crops.
One of the biggest concerns with European Buckthorn is that it grows very thickly and drastically alters the understory of forests. Like most invasive species, it lacks natural predators to curb its growth. It grows out-of-control very quickly.
How Can I Help? Removing European Buckthorn is Easy!
What it lacks in blistering toxins, though, it makes up for in tenacity.
Like most invasive plants, removing European Buckthorn is a multi-year commitment. The seeds can survive in the soil for years, even after you’ve killed the other plants.
Let’s break down European Buckthorn removal strategies based on the severity of the infestation.
- Just a few seedlings. With plants that are under about ⅜ inch thick, you can generally pull them out by hand. These plants are small enough that they won’t re-sprout.
- Lots of seedlings. Spray the area with Glyphosate (RoundUp) or Triclopyr to kill the European Buckthorn. When applied properly, Triclopyr won’t kill the grasses in the area.
- You can also cut the seedlings to stumps, then paint on the herbicides. If you’ve got a heavy infestation, put dye into the herbicide so that you know which stumps have already been treated.
- If you’d like to avoid herbicides, you can cover the stumps with a tin can or a black plastic “Buckthorn Baggie” to prevent re-sprouting.
- Adults (with or without seedlings). Simply cutting European Buckthorn down won’t kill it. You will need to use a combination of cutting the plant as short as possible (using shears or even a small saw) and other methods to prevent re-sprouting. With adult plants, you can either paint on herbicides (as described above) or cover the stumps (as described above).
- The most effective time for removing Buckthorn is late spring or fall. Don’t waste your time in May or June, when the plant is more likely to re-sprout easily.
- I just want to help my area. Most areas with European Buckthorn infestations will have volunteer days. Check with your local Department of Natural Resources (DNR) or Forest Service to see if there are any upcoming volunteer days.
Don’t forget that you’ll need to come back to double-check for re-sprouted European Buckthorn for several years. Unfortunately, this plant requires constant vigilance to control.
With your help, we can control European Buckthorn across the U.S. Even if you don’t have European Buckthorn in your backyard, we urge you to help your area by volunteering. As fall rolls around, it’s prime time for Buckthorn removal!