Making a Plan
Do you have one or two buckthorn trees or acres of buckthorn? Your situation can affect how you plan your treatments.
One way to start is by targeting your buckthorn plants that are producing fruit. Remove these fruit-bearing trees first and that will reduce the amount of seeds added to your soil each year.
Buckthorn seeds in the soil can continue to germinate for many years. Buckthorn management is a multi-year commitment. Once you've removed buckthorn plants you will need to follow up over time to remove the plants that continue to germinate.
Ways to prioritize management:
- Remove trees with fruit first
- If you have areas with relatively few buckthorn trees, start your management there and keep the nice areas nice. Then work towards the areas that are more heavily infested.
- Continue to follow-up in the areas where you have previously removed buckthorn.
Controlling seedlings or small buckthorn plants without cutting
Pulling individual plants
If less than 3/8 inch in diameter, plants can be removed 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 to ensure there are no buried utilities in the area. Hand-pulling tools can cause soil disturbance so work to minimize soil disturbance and tap soil and plants back into place after pulling plants. Disturbed soil may result in increased seed germination.
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. If you wish to use a cutting method, see the section below.
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 covering or treating the stump to prevent re-sprouting. Cutting can be effectively done with hand tools (for a few plants), chain saws or brush cutters.
Non-chemical control options for cut stumps include covering the cut stump with a tin can or black plastic (such as a "Buckthorn Baggie") to prevent re-sprouting. After cutting the tree, apply the can or plastic over the cut stump and root flare. Use nails to affix the can or a tie to affix the black plastic. Leave in place for one to two years.
Chemical control options for cut stumps include treating the stump immediately after cutting (within 2 hours) with a herbicide containing triclopyr (Garlon 3A/Vastlan, Garlon 4, or other brush killers with triclopyr) or glyphosate (Roundup) to prevent re-sprouting. Always follow label instructions for herbicides.
The most effective 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 most brush killers, Garlon 3A/Vastlan, 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 late fall and 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/Vastlan, many brush killers, etc.) can be applied to cut stumps when the temperature is above freezing (32 deg. F). Oil-based products of triclopyr ester (Garlon 4, Pathfinder 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 should be left standing and cut at a later date.
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. Follow-up control options include treating the buckthorn seedlings and samplings using the pulling, cutting, and chemical methods described above. Fire also offers a long-term management option in grassland or savanna cover-types. Burning will need to be done every two to three years.
After buckthorn control, many sites will benefit from replanting of desirable tree, shrub, and herbaceous species. This will minimize bare ground which is often colonized by invasive species. The DNR's Restore Your Shore resource may help you to find the right plants for your location. The University of Minnesota recommends planting grass mixes such as red fescue, oats or Virginia wild rye and native shrubs including as high-bush cranberry, nannyberry, chokecherry, pagoda dogwood, gray dogwood, elderberry, American hazelnut and black chokeberry.
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, Vastlan||Triclopyr amine||Mix one part Garlon 3A with 3 parts water|
(this achieves a 25% solution), for Vastlan consult label
|Garlon 4 Ultra, Element 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 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 on this webpage 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:
- Woody vegetation control
- Use the MIPN Control Database to find specific management recommendations for your type of site and experience level.
- Buckthorn: what you should know and what you can do
- Buckthorn: A threat to our Native Woodland Ecosystem (Janet Van Sloun Larson)
- What's Working: Common and Glossy Buckthorn Control by the Board of Water and Soil Resources
- Noxious weed disposal in Minnesota (MDA)