Late September through the end of October is a good time to inventory common buckthorn on your property. Common buckthorn leaves remain green longer than most Minnesota native trees and shrubs so they will stand out when other trees and shrubs are changing color and dropping leaves.
Common buckthorn (Rhamnus cathartica) can be found in upland forests. Look for the thorn, which can be found at the end of some branches.
Glossy buckthorn (Frangula alnus) can invade wetlands. There are no thorns. Look for the rust colored terminal bud.
See the buckthorn fact sheet for tips to identify buckthorn, learn about native look-alikes, and find methods for controlling buckthorn.
For a safe way to treat buckthorn stumps, you can apply herbicide with buckthorn blasters/dobbers: https://landscape-restoration.com/
See the DNR's buckthorn management page for more information.