You’ve Cleared the Buckthorn - Now What??
Sarah Heidtke, Dakota County Master Gardener
Buckthorn! It’s not native to Minnesota but it has made itself quite comfortable here, hasn’t it? Read on, as Dakota County Master Gardener Sarah Heidtke discusses some actions to take for buckthorn management after you’ve cleared this invasive plant species out of your property.
You’ve put in the work to clear your property of buckthorn. Congratulations! According to the Minnesota Department of Natural Resources, buckthorn management is going to be a multi-year commitment. Why? Well, viable seeds in the soil can germinated for two years, and additional seeds can come in thanks to birds and other wildlife.
The next steps to keep re-infestation of this invasive plant under control fall under three categories:
Add more desirable new plants to minimize bare ground where invasive plants can take hold.
Manually remove new buckthorn sprouts that come up - especially in the spring when they are easier to pull and again in the fall. Prioritize any berry-producing plants and if you can, work with your neighbors so that they do the same.
Use herbicides for larger plants, following all labels and instructions.
Determining what to plant next depends on your site conditions. University of Minnesota’s May 2024 “A guide to forest understory revegetation to help manage buckthorn and other invasive plants,” offers some great advice and a list of seed mix retailers. The goal is to out-compete new buckthorn sprouts, so seeding soon after large buckthorn removal is best. If the tree canopy has at least 10% of visible sky looking up from the ground, cool season grasses and wildflower seeds can germinate and grow quickly, making it harder for new buckthorn seeds to sprout. More shade-tolerant wildflowers can help suppress buckthorn in darker wooded areas, but you’ll need to be diligent about pulling buckthorn sprouts while the native plants get established. Native shrubs such as high-bush cranberry, nannyberry, chokecherry, pagoda dogwood, gray dogwood, elderberry, American hazelnut and black chokeberry are all identified by the University of Minnesota as healthy replacements for buckthorn.
Keep removing new buckthorn plants! Once all buckthorn has been cleared from your land, plan on walking your property to find and pull new buckthorn plants. The best time to find buckthorn is fall and early spring, when most plants other than buckthorn will be without leaves (MN DNR). Prioritize removing all of the berry-producing vegetation, in order to limit the ability of the buckthorn to expand. If the plant is too big to pull, the MN DNR suggests cutting the plant a few inches above the soil, and then preventing photosynthesis by either covering the stump with a can or dark bag or leaving a higher stump and continually removing any new green sprouts. See more instructions here.
There are times when some property owners consider chemical herbicides as the best option for larger plants. Mid to late fall is ideal for applying herbicide, as the plant's sap flows toward the roots, allowing for maximum absorption. Since buckthorn keeps its leaves longer than most plants, you can minimize harm to other species that are dormant for winter (UMN Extension).
Always follow product labels for safety and application directions. The label is the law. For more information on best practices for herbicide application, please refer to UMN Extension here: https://extension.umn.edu/yard-and-garden-news/fall-good-time-remove-buckthorn. If you are treating near water, the MN DNR requests that you first contact the aquatic pesticide enforcement specialist for advice on less harmful herbicides for aquatic species.
Buckthorn management is both a continual task and a community effort. Several cities in Dakota County also offer resources:
Eagan https://cityofeagan.com/buckthorn
Apple Valley https://www.applevalleymn.gov/679/Buckthorn
Burnsville https://burnsvillemn.gov/818/Buckthorn
Mendota Heights https://mendotaheightsmn.gov/537/Buckthorn-Removal
Additional online references:
Buckthorn management does take commitment but know that you are building a healthier environment and growing some lovely plants in its place.
Photo Credit: Sarah Heidtke (1,2,4), University of Minnesota (3), Michael Schuster, PhD University of Minnesota (4)