Buckthorn Removal in Wisconsin: NR 40, Plan and Cost

Common buckthorn is a Restricted invasive species everywhere in Wisconsin under NR 40, the state’s invasive species rule, which limits moving it off your land to disposal with no seed escaping. Clearing it so it stays cleared takes a mulching pass, return cuts for the stump sprouts and, if you choose, stump treatment by a licensed applicator. Clearing buckthorn from a woodlot understory or a fence line typically runs $1,500 to $2,500 an acre.

Walk a Wisconsin woodlot in early November and the shrub layer gives itself away. The maples and oaks have dropped their leaves, the native shrubs are bare, and a green band of buckthorn still fills the space under the canopy, often thick enough that you cannot see the next fence post.

What NR 40 Says About Buckthorn

Wisconsin’s invasive species rule, chapter NR 40 of the Administrative Code, sorts regulated species into two categories, prohibited and restricted. Common buckthorn (Rhamnus cathartica) and glossy buckthorn (Frangula alnus) both appear on the restricted plant list in NR 40.05, and neither entry is limited to named counties, so both are restricted across the state.

For a restricted species, NR 40.05(3) says no person may “transport, transfer or introduce” it. Possession is not on that list: the rule governs moving and spreading buckthorn rather than having it grow on your land. The rule also carries an exemption that matters for anyone clearing a thicket: a person may transport a restricted species “for the purpose of identification, education, control, or disposal” without a permit, “if no viable individual specimens or propagules are allowed to escape or be introduced.”

In practice that means a trailer of cut buckthorn hung with ripe berries has to reach its disposal site without dropping seed along the way. Grinding the brush where it stood never puts it on the road at all, which is one reason forestry mulching suits buckthorn work.

How to Recognize Buckthorn and How It Spreads

Common buckthorn is a tall understory shrub or small tree that reaches 20 to 25 feet. The field marks:

• Bark: gray to brown, with prominent light-colored lenticels (small raised pores).
• Leaves: mostly opposite, 1 to 2.5 inches long with tiny teeth, and they stay green into fall.
• Fruit: abundant clusters of round, black, pea-sized berries.
• Twigs: often end in a stout thorn, which is why a buckthorn thicket is miserable to walk through.

It takes hold in oak forests, riparian woods, savannas, prairies, old fields and roadsides. Fence lines and woodlot edges are where most landowners first notice it.

Birds plant it. Birds and mammals spread the seed, and the berries have a laxative effect that moves the seed quickly across the landscape. Birds perch on fence wire and along field edges, so new buckthorn tends to come up in lines.

It shades out what grows beneath it. Buckthorn creates dense shade that stops tree seedlings and understory plants from regenerating, and it is allelopathic, producing compounds that hold back other plants. A woodlot left to it long enough has no young oaks coming along to replace the old ones.

Fall is when to look. Fall is the best time to find invasive shrubs, because their leaves stay green longer than native trees and shrubs. A walk in late October or November shows how far the buckthorn reaches before anyone prices the work.

Why One Cutting Fails

Cutting buckthorn down does not kill the root. Cut without further treatment, it readily resprouts from the stump. A stem cut once comes back as several, and a thicket cut with a chainsaw on a fall weekend is often denser two summers later.

A forestry mulcher cuts every stem in a thicket at once and grinds stumps flush with the ground, but it does the same thing to the root as a saw does: nothing. That is why a mulching pass is the first step, not the whole job. Covering cut stumps with a tin can or black plastic stops regrowth on a handful of yard stems but does not scale to acres.

Timing helps explain why the fall matters. In autumn buckthorn is still active and moving nutrients down to its roots for winter, which is why stump treatments are aimed at that season. Meanwhile, birds keep carrying in seed from plants on neighboring land, so even a well-cleared woodlot will see new seedlings.

A Multi-Visit Plan That Holds

Here is the plan for a woodlot understory, a fence line or a pasture edge.

1. Scout in late fall. Walk the ground when the buckthorn is the only green left, and flag the oaks, maples and native shrubs you want kept. Each keeper is a point the machine works around.
2. Mulch the stand on the right date. Around oaks you are keeping, avoid cutting or wounding them from April 1 in the South Zone, or April 15 in the North Zone, through July 15. Late summer, fall or frozen ground in winter is the safer window, and frozen ground also spares soft soil.
3. Decide on stump treatment. Cut-stump treatment is done in late fall and basal bark treatment from late fall through winter. If you want either, that is a licensed applicator’s work, scheduled to follow our pass while the stumps are fresh. Cut Brush does the mechanical work only.
4. Cut the sprouts the next growing season. Return visits take the regrowth down while it is small and before it fruits. Plan on at least the following season, and longer where the stand was old and dense.
5. Pull the seedlings. Hand-pulling or a leverage tool handles small plants, which is the cheap way to deal with seedlings coming up in the chips.
6. Look again each fall. The green-in-November check shows whether the plan is working and where the birds have planted new stems.

Pro tip: Book the return visit when you book the first pass. The sprouts in that first summer are the ones that decide whether the thicket comes back.

What Buckthorn Removal Costs in Wisconsin

Clearing buckthorn and brush from under trees you keep, or off a fence line, typically runs $1,500 to $2,500 an acre, the buckthorn and understory band on our Ellsworth pricing page. An old, wide thicket with heavy stems prices as forestry mulching, $1,500 to $4,000 an acre.

Job	Typical range	Notes
Buckthorn and brush under trees you keep, or along a fence line	$1,500 – $2,500 per acre	Long, narrow lines are counted by their acreage equivalent
Old, dense thicket with heavy stems	$1,500 – $4,000 per acre	The forestry mulching band; slopes sit higher
One short fence line or a backyard stand	about $1,500 minimum charge	Where small jobs start, not a fee added on top
Return visits for sprouts	Priced per visit	Each one on its own line in the quote
Stump treatment	Separate trade	Quoted by a licensed applicator

Each pass grinds stems and stumps into mulch on site, flush with the ground, and hauls nothing away. Full stump removal below grade, and cutting and hauling very large trees, are discussed and priced in the quote; grading is not part of our price.

Inside the band, the price moves with the stem count, the slope, how many keeper trees the machine steers around and how far it travels along a line. The Ellsworth forestry mulching cost guide explains how coulee ground moves a quote and how to compare an hourly bid with a per-acre price.

Buckthorn Around Ellsworth, Pierce County and the St. Croix Side

In west-central Wisconsin, buckthorn work meets two local complications. The first is slope. Part of Pierce County, and most or all of Pepin County, lies in the Western Coulees and Ridges, Driftless country of steep-walled valleys and ridges, where a thicket that is quick work on a ridge field is slow on a coulee side. The second is oak: oak and hickory make up about half the forest in that landscape, so the oak wilt calendar shapes when a woodlot can be cleared.

Our crew clears buckthorn around Ellsworth, Prescott, Elmwood and Plum City in Pierce County, Baldwin, Hammond and Roberts in St. Croix County, and Pepin. See land clearing around Ellsworth for the towns and the local permit offices. Across the Mississippi in Red Wing or Lake City, Minnesota’s rules apply instead of NR 40; our Twin Cities buckthorn guide covers the Minnesota side. Bush honeysuckle, which often grows with buckthorn, has its own NR 40 rules; our Wisconsin bush honeysuckle removal guide covers them.

Frequently Asked Questions

Is buckthorn illegal in Wisconsin?

Common and glossy buckthorn are restricted statewide under NR 40. No one may transport, transfer or introduce them; the restrictions cover moving and spreading buckthorn, not having it grow on your land.

Can I haul cut buckthorn to a brush site?

NR 40 allows transport for control or disposal without a permit if no viable plants or seeds escape on the way. Fruiting brush needs to be contained; mulching it in place avoids the question.

Will mulching kill buckthorn?

Not by itself. It clears the stand in one pass, but the stumps resprout. Return cuts, and stump treatment by a licensed applicator if you choose it, are what keep it gone.

When is the best time to clear buckthorn?

Late summer through winter. Fall is when the buckthorn is easiest to see and when stump treatments are aimed, and work near oaks belongs outside the April to July 15 oak wilt season.

Get Buckthorn Off Your Wisconsin Land

Request a free quote and we’ll contact you to discuss your property, access and the clearing you need. Our crew plans buckthorn work in the order that holds: flagged, mulched, cut again as it sprouts, and checked the next fall.

Read more: statewide clearing costs and rules in the Wisconsin land clearing cost guide.