RANIER - Do you know what common buckthorn looks like and why it's a growing problem in Koochiching County?

Staff with the Koochiching Soil and Water Conservation District brought buckthorn education to a group gathered Wednesday at the Ranier Community Building.

James Aasen and Jolen Simon, of KSWCD, brought buckthorn plants with berries to the presentation to help those attending to identify it, as well as provided techniques for control, including use of a buckthorn wrench and herbicide, both of which can be checked out from KSWCD at 501 Third St., Suite 201, in International Falls.

They joked that as people drove from the community building, they would now see it clearly because they know what it looks like and it's among the very few plants that still have green leaves.

And, they noted, the Ranier area is a hotbed of buckthorn spread, with plants growing along County Road 20. In International Falls, buckthorn is growing along Keenan Drive.

Aasen and Simon urged anyone with questions about identification or management to contact them at the office by calling 218-283-1180, visiting the office, or seeing the website at https://koochichingswcd.org/ .

A woman attending Wednesday arrived with a sample of greenery in a plastic bag, asking if it was buckthorn.

It was, and then she was ready to find out what to do.

For those unsure of what the weed looks like and why it's a problem, they provided an overview of terms: non-native, using as an example the Amur Maple found near Backus Community Center; noxious, pointing to wild parsnip and poison ivy; and invasive, pointing to buckthorn.

Non-native noxious and invasive plants must be priority for control, Aasen said.

Resources must be focused on plants causing problems in Koochiching County, they said. Among the plants of concern locally are Knapp weed, a non-native high invasive plant; Canada thistle, a non-native aggressive invasive; purple loosestrife, a non-native invasive; common tansy, a non-native invasive; wild parsnip, a noxious invasive.

However, they said, "the weed of the day" is European, or common, buckthorn, which is now at a point where property-owner control or management of the weed could help stem its quick spread.

What is it?

Buckthorn, native to Europe and Asia, is a highly invasive perennial understory shrub or a small tree that can reach heights of 20 to 30 feet and 10 inches in diameter. The species was introduced to North America as an ornamental shrub and used for living fence rows and wildlife habitat. Since its introduction, it has spread aggressively across most of the northeast and upper Midwest and has become a serious threat to the degradation of native forest understory habitats where it out-competes native plant species.

Buckthorn is a problem, KSWCD staff say, because it:

  • Out-competes native plants
  • Degrades wildlife habitat
  • Threatens the future of natural habitats
  • Forms a layer of vegetation making it hard for wildlife and people to move through
  • Has no natural controls, such as insects or disease, that curb its growth

The Minnesota Department of Agriculture offers the following to identify buckthorn:

  • Tall understory shrub or small tree with a spreading/branched crown. Multiple stems at the base when young; eventually developing into a singular trunk/stem as it matures. Plants are either male or female.
  • Main stem can be up to 10 inches in diameter with brown bark and has elongated thorn-like projections. Cut stems have orange heartwood (center/non-living) and yellow sapwood (outer/living part of stem).
  • Branches contain buds and leaves that are mostly opposite or sub-opposite and terminate in small sharp thorns (up to ¼ inch in length).
  • Leaves are distinctly egg-shaped, smooth, glossy, finely toothed, pointed at the tip, and have three to five curved leaf veins that extend from the leaf stem to the tip. Leaves stay green late into the fall after most other trees have shed their leaf canopy, making buckthorn easy to identify at this time of the year.
  • Small yellow-green, four-petaled flowers are produced in clusters near the base of the leaf stalks along the branches. Male and female flowers are borne on separate plants.
  • Round berries are produced in the flower clusters of female plants following fertilization and ripen in August and September. Ripened fruit is black and shiny, highly attractive to birds, and contains three to four seeds each. The berries have laxative qualities, adding to the quick spread by birds.


Aasen said control can take two forms: Pulling up seedlings - by hand or wrench by the roots, noting it's often easier after a rain; use of herbicide to stumps to kill the plant at the root.

A buckthorn wrench allows the user to pry up the larger plants that cannot be hand pulled, often easiest to do on first-year seedlings.

Plants more than 2 inches in diameter can be killed by cutting and then applying an herbicide to the outer ring of bark with a dabber, which keeps herbicide from affecting other plants.

Once the plants are removed, especially if they sport berries, it's important that they be burned, or taken to the county's transfer station and telling the attendant there that the plants are an invasive species, so they may be properly disposed.