By Scout Nelson
A new study from the University of Minnesota highlights an effective way to control common buckthorns, one of the most invasive plant species in Minnesota. Researchers found that planting native grasses and wildflowers immediately after removing buckthorn greatly improves long-term control and reduces the chances of the invasive shrub returning.
Buckthorns are difficult to manage because they often grow back after removal. This creates ongoing challenges for land managers who work to restore forests and natural habitats. To find the best solution, researchers studied different methods of controlling buckthorn regrowth after initial removal efforts.
The study showed that applying the herbicide fosamine ammonium (Krenite) to buckthorn leaves during the year following removal effectively kills many remaining plants. Researchers also found that a second herbicide application two years later can nearly eliminate buckthorns from treated areas.
Results indicated that delaying the first follow-up treatment for several years is much less effective. Early action allows managers to control regrowth before buckthorn becomes established again.
Researchers also discovered that adding native grasses and wildflowers after the first treatment plays an important role in suppressing buckthorn seedlings. Native plants compete for sunlight, water, and nutrients, making it harder for invasive plants to return. This approach works especially well in areas where tree cover is less dense.
“There is no silver bullet for defeating buckthorn, but our work shows that control is possible with hard work and patience,” said lead author Andrew Kaul, a former postdoctoral researcher in the College of Food, Agricultural and Natural Resource Sciences, currently with the Missouri Botanical Garden.
“This work shows how treating resprouts with herbicide and seeding early on in management is key to successful restoration efforts,” said Mike Schuster, a researcher in the College of Food, Agricultural and Natural Resource Sciences.
The findings suggest that restoration efforts should begin as soon as possible after buckthorn removal rather than waiting until later seasons. Early seeding of native species provides long-term benefits for forests and helps build healthier ecosystems.
Researchers are continuing to test different native seed mixes, planting methods, and restoration strategies to improve environmental outcomes and support biodiversity.
Photo Credit: istock-georgeclerk
Categories: Minnesota, General