Buckthorn! It’s the bane of many Minnetonka home owners, and it’s not here by accident. Buckthorn was introduced to the US from Europe. There is a glossy and a common type, both are columnar and were once sold in the nursery trade as hedging material. We are most likely to encounter common buckthorn in our area.

The only good news? September is the time to start buckthorn removal! The leaves will be off the trees and shrubs soon, so even the cover buckthorn provides won’t be missed. A little know-how goes a long way, including next-steps after removal.

Identify

In just a few weeks we’ll be in one of the easiest times of year to identify and remove buckthorn. Middle to late October is particularly great because native species (think Black Cherry, Pagoda dogwood, Hawthorn, etc.) will have lost their leaves while Buckthorn will still have leaves for a while longer. This makes it easier to identify the invasive from valuable natives. We recommend marking native trees and shrubs with a flag or ribbon to ensure there are no mistakes.

Common buckthorn has toothed leaves that are egg shaped, dark green, and somewhat glossy. The bark is greyish brown, and rough on older plants. In fall, buckthorn has black berry clusters that will drop and create new plants.

Buckthorn bark exposed

Buckthorn heartwood has a telltale orange color.

Go to the Minnesota Department of Natural Resources website for more information on identifying buckthorn.

Remove and Treat

Removal is labor intensive. Buckthorn can be removed with any tool that can cut off, tear out, our remove a branch, trunk or roots. Hand pulling works for small seedlings. For larger pieces use a hand saw, bypass pruners, loppers, chainsaw, or the wrath of the gods if you have those connections.

It’s easy to get ahead of oneself and cut a large number of stems, only to lose sight of some them later. We recommend cut three, treat three. Make three cuts, then treat those cuts with chemical, and move on to the next three cuts. To avoid inadvertently cutting the same twig twice, and to keep track of where you’ve been and what might have been missed, add a bluing dye to the chemical to color the cut. Mrs. Stewart’s Liquid Bluing works well (plus if you have any left over, you can whiten your whites in the wash!).

Chemical control is absolutely necessary. These are not regular weeds. The chemicals are harsh (though they are considered non-toxic to humans, there is no reason to risk exposure), so be careful, wear long sleeves and pants and thick gloves. Wash any skin that has been exposed immediately, and change clothing.

Two solutions are recommended by the majority of buckthorn removal experts and we carry two products that contain these ingredients.

  • Bonide KleenUp – The active and recommended ingredient in this product is glyphosate.
  • Bonide Stump and Vine Killer – The active and recommended ingredient in this product is triclopyr. This can be used in winter since it can penetrate frozen bark and wood.

Either of these is acceptable. Just cut and apply. Do not drill holes in stumps, there is no need and it only risks unnecessary exposure.

What Not to Do

Clearcutting buckthorn is not recommended, as it can allow for other irritating invasives (such as garlic mustard) to move in, it can result in the unwanted removal of good native trees and shrubs, and it can cause erosion.

Replace

Buckthorn takes over spaces where native plants should be growing. These important plants support native pollinators and wildlife. Buckthorns aggressive nature means it must be treated consistently to allow natives to become established. Add woodland natives such as Virginia bluebells. Even more aggressive natives, such as Virginia creeper, are more desirable than buckthorn. If garlic mustard is a concern, plant groundcover ginger, which has the ability to compete with the mustard.

Time to get a jump on these nasty weeds!