Buckthorn

Invasive species

Nature

Most of these invasive plant factsheets are created from the booklet Minnesota invasive non-native terrestrial plants, an identification guide for resource managers.

Check the additional resources and herbicides table for more information.


What you can do to control buckthorn!

Removing small buckthorn with hand tools
Removing small buckthorn with hand tools.

Controlling seedlings or small buckthorn plants

For individual plants

If less than 3/8 inch in diameter, remove by hand. Small seedlings can be pulled and will not re-sprout. If greater than 3/8 inch, use a hand tool that pulls the shrub out, such as an "Uprooter" or "Root Talon".  Removing by hand is easier if the soil is moist. Before you pull or dig buckthorn out of your soil, Contact Gopher State One Call (1-800-252-1166) to ensure there are no buried utilities in the area.  Be aware of minimizing soil disturbance and tap soil and plants back into place after pulling plants.

If pulling individual plants is impractical

Spray foliage of short buckthorn or seedlings with a herbicide. Glyphosate (one brand name is Roundup) will kill all actively growing vegetation on which it is sprayed. Triclopyr will kill broadleaf plants and will not harm grasses when applied properly.

Controlling large buckthorn

Buckthorn plants that are two inches in diameter or larger, are best controlled by cutting the stem at the soil surface and then cover or treat the stump to prevent re-sprouting. This can be effectively done with hand tools (for a few plants), chain saws or brush cutters. If only cutting a few stumps they can be covered with a tin can or black plastic (such as a "Buckthorn Baggie") to prevent re-sprouting. Otherwise, stumps should be treated immediately after cutting (within 2 hours) with a herbicide containing Triclopyr (such as Ortho Brush-B-Gon or Garlon 3A or 4) or Glyphosate (Roundup) to prevent re-sprouting.

Hand tools for cutting buckthorn
Hand tools for cutting buckthorn.

The best time to cut and chemically treat the stumps is in late summer and throughout the fall. Avoid treating buckthorn in May and June when the tree is putting out leaves as the herbicide will be less effective at this time then during the rest of the year.  Herbicides can be applied to cut stumps with a paint-brush, wick applicator or a low volume sprayer. When using water-soluble herbicide products like Ortho Brush-B-Gon, Garlon 3A, or any of the Glyphosate products, treat only the cut surface. When using oil-based products like Garlon 4 or Pathfinder II, treat the cut surface and the remaining bark to the ground line. In cases where more than a few plants are treated, add an indicator dye (available where pesticides are sold) to the herbicide to mark cut stumps you have sprayed. Colored flags can also help mark cut stumps. When buckthorn is cut, the stumps are easily covered and lost under cut brush. 

Chemical treatment in the winter: Buckthorn can be treated throughout the fall and winter.  Follow herbicide label instructions regarding temperatures at which the herbicide can be applied.  Water-soluble herbicides like glyphosate (Roundup, Rodeo, etc.) or triclopyr amine (Garlon 3A, Brush-B-Gone, etc.) can be applied to cut stumps when the temperature is above freezing (32 deg. F).  Oil-based products of triclopyr ester (Garlon 4, Pathfnder II) can be applied when the temperature is below freezing (below 32 deg. F).

For basal stem treatment, a method that applies chemical through the bark, low volume spray applications can be made with Garlon 4 and similar oil-based products. This application method uses Triclopyr ester mixed with an oil diluent ( i.e. Bark Oil Blue, kerosene or diesel oil) applied directly to the bark of buckthorn from the root collar up about 12-18 inches. This treatment works best on stems less than 2-3 inches in diameter. An ultra low volume spray wand should be used to minimize herbicide use and reduce the potential for non-target injury. Buckthorn treated in this fashion can be left standing or cut at a later date.

Applying chemicals to cut buckthorn
Applying chemicals to cut buckthorn.

Note: Buckthorn seeds in the soil can remain viable for up to five years. Follow-up control of seedlings that emerge after initial control efforts is important on all sites. With no follow-up control, buckthorn will come back. Fire offers a long-term management option in grassland or savanna cover-types. Burning will need to be done every two to three years. If burning is not an option, a follow up treatment of the seedlings (pulling or spraying) is needed.

After buckthorn control, many sites may require replanting of desirable tree, shrub, and herbaceous species. A resource that may help you to find the right plants for your location is a multimedia CD program called Restore Your Shore.

 

Herbicides to Control Buckthorn

Trade Name Chemical Name Concentration Use
Ortho Brush-B-Gon Triclopyr amine Ready to use - do not dilute Cut stump
Ferti-Lome Brush Killer and Stump Killer Triclopyr amine Ready to use - do not dilute Cut stump
Garlon 3A Triclopyr amine Mix one part Garlon 3A with 3 parts water (this achieves a 25% solution) Cut stump
Garlon 4 Triclopyr ester Mix one part Garlon 4 with 3 parts bark oil/diluent (this achieves a 25% solution) Cut stump or basal bark
Pathfinder II Triclopyr ester Ready to use - do not dilute Cut stump or basal bark
Roundup, Rodeo, Accord, Etc. Glyphosate
  • Cut stump: Look for at least 25% active ingredient glyphosate for cut-stump treatments. If using Roundup Concentrate you can mix 1 part water with 1 part herbicide to achieve a 50% solution. 
  • Foliar spray: Lower concentrations (2% active ingredient) work for foliar spray of seedlings.  If using Roundup Concentrate you can mix a 1:50 to 1:20 herbicide:water ratio.
Cut stump or foliar spray

Always read and follow the instructions and precautions on the herbicide label.

Reference to chemical brand names and other product brand names in this column does not imply endorsement of those products. The herbicides listed in this article may be available under other brand names with the same active ingredient that are equally effective.

Biological control: There has been research to find biological control insects for buckthorn, but no suitable insects were found.

Additional management information: