Wednesday, December 23, 2020

Buckthorn at Long Lake by Dante Beretta

European Buckthorn Seedling.  Note the finely toothed leaf.

While exploring the woods at our Long Lake property this summer, I discovered a small patch of European Buckthorn. Also known as Common Buckthorn, the plant was introduced in Minnesota for use as a plant in hedges.

European Buckthorn can grow to 20 feet in height. It is aggressive in growth, creating dense shade and crowding out native wildflowers and other plants from the under-story. During the Fall, the leaves stay green being one of the last plants to lose leaves. The fruit is cathartic, meaning it causes diarrhea, allowing it to spread easily by birds eating the fruit.

If feasible, it is a good idea to remove this plant from your property or at least control its spread. The first part of removal or control is to accurately identify European Buckthorn. The Minnesota DNR website is an excellent resource for the identification and management of Buckthorn.

Also, Midwest Invasive Species Information Network (MISIN) has a quick course on identifying Buckthorn. This website presents key features of the plant and it took me less than 5 minutes to complete the course and quiz.

Another way to learn to identify Buckthorn is through using a smartphone app called 'Picture This'. You take a photo that the app compares to its database. The app is accurate in its recognition of Buckthorn and other plants in the Long Lake area.

Buckthorn with fruit. Priority is given to
removing this phase of the plant to prevent
The Buckthorn ‘infestation’ on my property was about 20 seedlings, so I removed them simply weeding by hand, making sure to pull out the roots. Some medium-size plants require digging to get at the roots. For large trees or extensive Buckthorn invasion, priority is given to trees that are producing fruit to control the spread. These plants are big enough that they usually need to be cut down and then require some additional work to prevent regrowth. I have been successful in using black plastic tied over the exposed stump.

Another method involves cutting the bark circumstantially around the trunk. With either of these methods, the application of a small amount of herbicide such as Glyphosate herbicide to the exposed cut of the tree trunk will be more effective in preventing regrowth. As seeds may germinate up to 5 years after, it is important to recheck the area and pull new seedlings once a year. Sometimes you will need to prune new shoots off of previously cut trunks. Once Buckthorn is eradicated, the woods reestablish with native woodland wildflowers and plants in the under-story. A healthy woods offers a better habitat for wildlife.

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