How Do You Get Rid of Buckthorn in Wisconsin?
You get rid of buckthorn in stages, and the follow-up runs about three years. Cutting or mulching knocks a thicket down, but the stumps send up new shoots. The UW Extension says a cut-stump treatment keeps the roots from regrowing. Repeated mowing or a foliar treatment keeps after the regrowth, and new seedlings need watching too.
Buckthorn turns woods into a wall of brush. This plan comes from what the Wisconsin DNR and the UW Extension publish. Paulin Land Solutions handles the heavy first step: buckthorn removal with a mulching head on a compact track loader. We never spray, so the herbicide step goes to a licensed applicator from another company.
What is buckthorn, and why does it take over Wisconsin woods?
Common buckthorn and glossy buckthorn are shrubs or small trees from Europe and Asia, 10 to 25 feet tall. A DNR forestry guide says they were planted in Wisconsin as ornamentals as early as 1849.
Both leaf out early and hold their leaves late into fall. The DNR says their dense shade stops tree seedlings and understory plants from coming up. It also calls common buckthorn allelopathic: it gives off compounds that hold back other plants.
Common buckthorn fills oak and maple woods, fence rows, old fields and pastures. A DNR forestry guide calls it a major problem in the oak woods of southern Wisconsin. Glossy buckthorn favors wetter ground. To check a shrub, cut a branch: buckthorn shows yellow sapwood around an orange heartwood.
Wisconsin’s invasive species rule, NR 40, lists both as restricted. The DNR encourages control but does not require it.
How does buckthorn spread through the woods?
Berries do the spreading. Common buckthorn plants are either male or female, and only the females carry fruit. The black berries are about a quarter inch across and ripen in late summer. They hang on into winter, after the leaves drop.
Birds and mammals eat the berries and carry the seeds off, often far from the parent plant. Glossy buckthorn fruit turns from red to black and spreads the same way.
Estimates of how long seeds last in the soil vary. A DNR forestry guide puts the seed bank at two to three years. Newer University of Minnesota research tracked more than 13,000 buckthorn seeds in the soil. It found that 97 percent of the seeds that sprout come up in the first year.
The DNR forestry guide says to take out the largest seed producers first when a patch is large. Every fruiting plant that comes down shrinks next year’s seed supply.
What are the ways to get rid of buckthorn?
The DNR and the UW Extension list several tools. Each one fits a plant size and a season.
| Method | Fits | When | Notes |
|---|---|---|---|
| Hand pulling | Seedlings up to about 0.4 inch thick | Moist soil | Pull the root crown too, or it resprouts |
| Digging or a leverage tool | Stems 0.5 to 1.5 inches thick | Before the plant sets seed | Tamp the loosened soil back down |
| Cutting or forestry mulching | Thickets and larger stems | Winter, or summer after leaf-out | Knocks it down; the stumps resprout |
| Mowing the regrowth | Resprouts and seedlings | Summer before seed, again in fall | Weakens plants but rarely kills them |
| Cut-stump treatment | Freshly cut stems | Late fall into winter, right after the cut | Keeps the roots from regrowing |
| Basal bark treatment | Standing stems up to 6 inches thick | Late fall through winter | Herbicide in oil on the lower stem |
| Foliar treatment | Seedlings and low resprouts | Leaves green and growing | Often follows a cut, on the regrowth |
The last three rows are herbicide work, and the UW Extension says to read and follow the label first. Cut stumps get treated no later than one hour after cutting.
Does cutting or mulching buckthorn kill it?
Not by itself. The UW Extension says forestry mowing chews woody stems into mulch but typically does not kill the roots. A buckthorn stem cut at the ground sends up new shoots from the stump.
Mulching still does the heaviest part of the job. Forestry mulching knocks the thicket down and grinds the stems into a mulch layer. Light reaches the ground again, and you can see and walk through your woods. The regrowth comes back low, where it is easy to keep after.
The extension service’s buckthorn fact sheet notes that mowed material mulched on the soil can reduce new seedlings. It advises against moving fruiting brush off a site unless the fruit cannot spread. Mulching in place keeps the berries on the property they came from.
Honeysuckle and prickly ash often share that understory. Brush clearing under mature trees takes them down too.
When is the best time of year to work on buckthorn?
Late fall. Buckthorn stays green after most native plants go dormant, so it is easy to spot. The DNR lists late fall for cut-stump treatment and late fall through winter for basal bark. A DNR forestry guide adds that fall herbicide work lowers the risk to native plants.
Winter. The UW Extension suggests mowing in winter when possible. That spares the plants you want and keeps the soil from compacting. The trade-off is resprouting: a UW Extension brush guide says roots store the most food from November to early May. Stems cut in that window resprout the hardest.
Summer. Root reserves hit their low point just after the leaves fully open in late spring. Stems cut after full leaf-out resprout the least.
Spring. Pull seedlings while the soil is moist. The UW Extension names early spring and late fall as the best times to check the woods for invasive plants.
How long does it take to get rid of buckthorn?
Plan on three years of steady work, then regular checks. The UW Extension’s sample buckthorn plan runs like this:
- Year one: Remove the adult plants, and take the ones with berries first. Treat the cut stumps or cover them with plastic bags, then reseed bare ground with native grasses and wildflowers.
- Year two: Finish off the adult plants. Pull the new seedlings or have them foliar treated.
- Year three: Very few seedlings should sprout by now. Keep treating any buckthorn that remains.
After that, birds keep bringing seed in from nearby land. A quick check each spring and fall finds new plants while they are small enough to pull. The fact sheet also notes that underplanting a shade-tolerant tree, such as sugar maple, holds buckthorn back.
What about buckthorn in wet ground?
Glossy buckthorn invades wetlands, including sedge meadows and fens. Wetlands fall under state rules, so ask the Wisconsin DNR before any machine work there. Herbicide near water needs a product labeled for aquatic use. The UW Extension adds that work in aquatic areas may call for a pesticide applicator license.
Where does Paulin Land Solutions fit in a buckthorn plan?
Our part is the first step. The mulching head on our compact track loader grinds the thicket to the ground. The mulch stays where it falls, and the mature trees you want to keep stay standing. The follow-up is yours to plan: mow the regrowth, or hire a licensed applicator for treatment.
We work across Waukesha County and Southeast Wisconsin, about 40 miles around North Prairie. See how we mulch buckthorn thickets, or read what forestry mulching costs per acre for market numbers. We look at the job and put the quote in writing. Call or text (262) 527-7619.