How to Kill Buckthorn

Last year we completed a small research study on how to kill buckthorn.  If you live in the upper Midwest then you’re familiar with this plant as a shrub which has escaped cultivation, been spread by birds, and generally made a nuisance of itself, particularly at the edges of forested land.

Buckthorn is notoriously difficult to kill after it gets more than about a foot high.  It laughs at single applications of roundup. If it’s pulled out of the ground any roots that don’t come with it have a good chance of sprouting shoots themselves, and it seems to enjoy being treated with organic herbicides like vinegar.  So, to try and kill bucktorn, we used an herbicide which had the active ingredient triclopyr.  This is an active ingredient which is usually great against all manner of weedy vines like poison ivy.  This herbicide is labeled for homeowner use and is available in most garden centers.

We applied this herbicide to buckthorn in the spring, summer and fall, and we used a few different application methods including painting the herbicide onto cut stumps and spraying it onto the leaves of uncut bushes, as well as painting the product onto the lower portion of stems.  Some of these application methods were experimental.  Do not attempt to apply an herbicide in any way besides that which is listed on the label!

That said, we found that the fall was by far the best time to apply the herbicide and that spraying the foliage wasn’t nearly as effective as other application methods, particularly painting the cut stem with the product after cutting it down.

17 thoughts on “How to Kill Buckthorn”

  1. The number of homes with large forested lots in the Twin Cities being overtaken by buckthorn is depressing. People just don’t know that a forest filled with buckthorn is not a healthy forest, even though the lower story is filled with green. Seems most of these large lot owners are please with the screen-like effect buckthorn has given them more than a functional forest.

  2. Friends in Atlanta had a hillside filled with kudzu. They cut it back to a foot from the ground, filled a can with liquid Round-up, and stuck the cut end in. They’d check it several times a day, filling the can back up. Though the other townhouses continued to have kudzu, they never had it come back (though they did have to watch that behind their neighbors). Maybe getting the plant to suck up poison really punches it out.

  3. I’ve killed quite a bit of buckthorn in my chicago area yard. I agree, the best way to get rid of it is paint the fresh cut stump with triclopyr. it works very well.

  4. uggh, so many summers spent spraying triclopyr, i think i got it in my blood. but yeah, cut stump spraying worked best for us… the Chicago forests are so heavily infested and the seed banks (in the soil) so numerous it seems like a losing battle… but i must say the woodlands do look a lot nicer after the initial removal…

  5. I spent 5 years eradicating it from 2 1/2 acres near St Paul. I found that spraying the cut stump with ortho Brush killer concentrate (straight not diluted) also worked. Now if my neighbor the environmental consultant would clean up his lot I would be 2/3 home free.

      1. I tried their product.. it was very hit and miss. If the baggies flared on the bottom and could be pinned to the ground around the buckthorn it might be better, but as it was, most of the buckthorns grew out from under the baggies. Many were removed by wild life. I may try nailing them to the cut stump with an added ‘skirt’ of contractor garbage bags, but the provided zip ties were not enough.

        1. I used the bags and had the same issue. Buckthorn just grew from under the baggies. It was a waste of money for me.

    1. I tried the baggie method. It was about 25% effective after 2 years. Part of the problem is the baggie needs to flare at the bottom and cover the roots near the crown. Another is the tiedown method does not work well and deer, and even ants, tend to move them. It might work stay in place if tacked to the stump. IDK. But I don’t recommend it any more due to these issues.

  6. For whatever it’s worth, I live near Duluth,MN and have thousands of seedling to 6’ high buckthorn on my property. After about10 years of experimentation ( basically cutting the buckthorn down to the ground every time it comes up) , I have resorted to the chemical method. Now keep in mind that I have cut almost all buckthorn down to the ground so any regrowth is at ankle to knee height. I finally came up with a plan of using Milestone during early summer times of active growth and using glysophate during the fall when buckthorn is the only plant with green leaves. Both methods work well. I use an empty winded bottle to minimize the amount of herbicide going out

  7. We have found much success by pulling the small starters and digging out small to medium trees. For larger trees we would cut them down so the stump is level with the grade. We then cleared a 2′ x 2′ area around the stump and laid two layers of black polyethylene sheet anchored down with landscape staples. The black color keeps the light out and “sterilizes” any sucker shoots. After one year the stump is dead and the plastic can be removed. We have also found that seeding areas where the small starts were pulled prevented re-growth. All items can be purchased at a big box home store. So far we have reclaimed about two acres of Oak Savanna.
    No chemicals to harm you or other desirable plants and trees.

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