Cover it Up! Expansion


Using plants to control buckthorn: an expanded approach

Peter Reich, Forest Resources


Minnesotans spend millions each year removing buckthorn (Rhamnus cathartica). Yet the invasive shrub often returns to the same spots again and again. This vicious cycle happens because buckthorn is better at filling empty spaces in an ecosystem than most other native plants.

“Cover it Up!,” led by MITPPC-funded ecologist Peter Reich, is developing strategies that will improve and diversify the native plant community while keeping buckthorn away for good. Phase I of the project established that dense revegetation through native shrubs can reduce buckthorn recolonization by blocking at least 96% of incoming light. 

With Phase II, detailed here, Reich’s team will expand their study from the Twin Cities metro into Greater Minnesota and explore how managers throughout the state can suppress buckthorn for the longest time and at the lowest cost. A network of citizen scientists will help carry out experiments in woodland areas across Minnesota. 

If effective, the revegetation treatments designed and tested here can serve as a template for managers throughout Minnesota, potentially resulting in significant cost and labor savings and improving the health of woodlands by excluding invaders, reducing herbicide applications, and increasing forest understory plant diversity.

Research questions

  • What native planting and seeding techniques can reduce the recurrence of buckthorn after removal? 
  • How effective are revegetation methods in environments across Minnesota?

Practical implications

This work could change the way we think about buckthorn management, helping Minnesota land managers save significant time and money in their long-term restoration efforts. If successful, it promises to improve the health of Minnesota forests by reducing herbicide applications and increasing understory plant diversity.





UMN Extensions, Stantec, Minnesota DNR, St. Croix Watershed Research Station, Three Rivers Park District, Ramsey County

Research Team:

Peter Reich, principal investigator

Peter Wragg, post-doctoral associate

Michael Schuster, post-doctoral associate

Abbie Anderson, citizen science coordinator


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