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Letter from Skunk Hollow: New buckthorn tools enable winter warfare

forest of invasive buckthorn

MinnPost photo by Ron Meador

Buckthorn eradication is the forest landowner's equivalent of a never-ending War on Terror.

A year ago, my journal shows, I snowshoed into the woods behind the house one afternoon, stepped out of a binding unawares, and sank up to — well, to the top of my inseam.

This year the snowshoes haven't left their hooks. Our cross-country skis are still wearing last winter's wax.  I've run the snowthrower exactly once, and that was optional, really — a shakedown run for the big dumps that still haven't come.

Our nearly non-winter isn't a completely happy thing, for I like a deep, cold month or two. But it has offered one unexpected benefit: thanks to mild weather and some new weapons and tactics I picked up in a training last fall, I've been able to keep fighting my war on buckthorn without a cease-fire.

And I'm finally optimistic about pushing this invader off my portion of Skunk Hollow.

Conventional wisdom's not so wise

Military metaphor isn't my style, but with buckthorn it has become a habit. The guys out here all seem to talk that way, pehaps because experience has taught them that buckthorn eradication is the forest landowner's equivalent of a never-ending War on Terror.

That might change if more listened to Cheryl Culbreth, a landscape-restoration professional whose message is:

Getting rid of buckthorn, permanently, is not only possible but may be far less work than many of us believe.

I heard Culbreth give a workshop on a sunny morning last fall at Camp St. Croix. The camp was having a Halloween festival and hundreds of parents and children, presumably untroubled by buckthorn in their personal lives, were gaily playing ring-toss or having their faces painted.

Away from the festivities, in a cramped, unheated shed, about 20 of us weathered warriors were listening hard as Culbreth explained that nearly everything we thought we knew about battling buckthorn was, well, not necessarily so.

From the questions and comments I heard, our collected knowledge and/or folk wisdom up to that point could be summarized thus:

The best way by far to clear buckthorn is to pull it up by the roots, because if  you just cut it down, it will regenerate – sending up many stems, hydra-like, from each stump you leave.

The next-best way is to spray the foliage, from early summer through fall, with a heavy-duty herbicide like glyphosate (introduced as Roundup) or triclopyr (Garlon, Crossbow, etc.).  But don’t start too early; when the trees are leafing out, the upward flow of sap will flush the herbicide away. And don't spray too little; if you don’t kill the root, get ready for the hydra.

If uprooting is too much work, and broadcasting plant poison is objectionable, there is always try the cut-stump method: cut the trees to leave several inches of stump, and immediately soak the cut and bark with a spray of triclopyr, diesel fuel (to slow evaporation) and a bright dye (to keep you from tripping over it later). If the stump is large, “frill” the bark first with a hatchet or machete to get more poison into the wood.

All of these methods are seasonal, and the cut-stump/triclopyr option has the narrowest window. To limit harm to other species, it's best to cut and spray after everything but buckthorn has gone dormant, but before the buckthorn drops its leaves. This leaves you maybe a month, give or take, and less if you deduct for Thanksgiving and deer season.

A series of defeats

tools for removing buckthorn
MinnPost photo by Ron MeadorThe old way: backpack sprayer with herbicides, weed
wrench, machete, hatchet and a chainsaw for good
measure.

Three years ago, having weighed the options, I decided to try them all. I invested in heavy weaponry including a backpack herbicide sprayer, a “weed wrench” supposedly capable of uprooting trees to a 2-inch diamater, a gallon of triclopyr and a couple of diesel, some red food coloring and a nice new machete with scabbard.

And then I lugged all this stuff into battle, only to meet one harsh reality after another:

  • The weed wrench proved capable of uprooting buckthron stems to half the rated size, but not easily — and beyond that size the root balls were too big to budge. Perhaps the worst $150 I ever spent on yard tools.
  • The backpack sprayer was kind of fun to use, for a guy who grew up on "Combat!" reruns and secretly coveted the flamethrowers, but after I watched the red mist drift away on light breezes my conscience called a halt to foliar spraying.
  • Cut-stump work went OK, except that the red dye makes the stumps more visible only briefly; come spring you've got a bunch of trippers to remove, just when you want another chore.
  • And it's hard to love the smell of diesel in the morning. It does not smell like … victory. More like an oil spill in my woods.

After three years of experimentation and intermittent toil, for the toil was no fun at all, I'd cleared only a handful of small patches and had disappointing re-growth results besides.

Light weapons and a long timeline

Culbreth’s strategy could be considered the guerrilla alternative to all the other battle plans — a fast-moving cut-stump approach that makes focused use of the most benign buckthorn-killer available and can be used 10 months of the year. Here’s how it works:

  • Gather some herbicide containing at least 18-20 percent glyphosate, some bright marker dye like the blue stuff favored by golf courses, and a small plastic bottle with a sponge-applicator tip. Fill the bottle with herbicide and a bit of dye.
  • Cut off the buckthorn stems just above the ground, and level (no trippers).
  • Daub the tinted herbicide lightly around the perimeter of the cut surface. Your target is the cambium layer just inside the bark, and you don’t need to soak it.
  • Cut and treat as much as you like from July through April. In really cold weather, you've got to keep the glyphosate from freezing; you can tuck the (capped) applicator inside your jacket or get a 40% preparation and mix it 1:1 with isopropyl alcohol.

One application  won’t do it all, but after just two or three years of intensive treatment you can expect to shift to maintenance mode, yanking up new plants that sprout not from the old stumps but from seed, and pull out readily (buckthorn seeds stay viable in the soil for up to seven years, and of course the birds are always bringing new ones).

clippers and herbicide
MinnPost photo by Ron MeadorThe future of buckthorn eradication: keep it light

Culbreth doesn’t criticize others' methods nor trumpet her own too loudly, although she cautions that the soil disturbance from uprooting essentially invites new invaders to move in. She'd rather see people removing buckthorn by any and all means rather than surrender to its spread, and she seems kind of modest besides. So I'll say it in her behalf — the method she's teaching is brilliant.

It takes less time and costs less money. It uses less herbicide and virtually eliminates the risk to nontarget plants.  You aren't restricted to the warm-weather months, when you may have pleasanter things to do. Above all, it's much lighter work, so a lot more land gets treated, and the frustration factor goes way, way down.

You leave the heavy gear behind and go for a walk in the woods, with lopping shears in hand and a little bottle in your pocket, and you can cut and treat all but the biggest trees just snip-snip-snip, daub-daub-daub. Come back later with a chainsaw for the rest.

In place of red-tipped trippers and the chore of clearing them next spring, I have little spots of blue in the snow. Next year there will be fewer of these, and fewer still the year after that. At which point it may be time to revisit Culbreth’s materials on the next big invasive threat — garlic mustard.

But one war at a time.

cut and dyed buckthorn stumps
MinnPost photo by Ron MeadorBuckthorn stumps, cut and dyed

* * *

Culbreth offers more information about this method, about buckthorn eradication generally, and about upcoming workshops on her website:  www.landscape-restoration.com. She also  sells supplies including a "Buckthorn Blaster" applicator developed by a former business partner, Mary Wright. You could probably make your own gear but hers is reasonably priced and works like a charm.

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Comments (8)

Thanks

Thanks Ron. You've probably saved us from an expensive investment in a weed wrench. But I wonder what kind of soil your buckthorn is growing in; ours is very sandy and maybe an expensive wrench would work better here in Pepin.

I had good luck with a weed wrench

But not on buckthorn. I rented one last fall to clear out a swampy area in my backyard that was playing host to hundreds of maple seedlings, ranging from pencil-thin to wrist-thick. It was hard work but it really did uproot all but a few of the largest. Took me three solid weekends.

If you think you might be able to use a weed wrench, I'd suggest renting one for $20 first.

Weed Wrench and Channellock

I've had pretty good luck with a 1 1/2 inch weed wrench. It has been used on hundreds, if not thousands, of small buckthorn trees, as well as honeysuckle, small elms and juniper. Any tree much over an inch in diameter may be too difficult to remove with the weed wrench. In these cases, I saw the trunk and paint with triclopyr. Seems to work pretty good.

A ten or twelve inch channellock pliers works great to uproot buckthorn with a pencil-thick trunk and smaller. Sometimes there are a dozen or more of these little stinkers in a square yard of ground. The channellock makes quick work of these.

Cleared 40 acres one summer

Girdle the large trees with a hatchet, exposing a ring under the bark. Chop downward and leave the bark hanging. Then with a spray bottle full of Tordon just spray all the way around. The trees will be dead by the next day.

More Advice

I've been removing buckthorn for 10 years. I now only have small plants that show up occasionally, and I have lots of oak seedlings and wild flowers that have moved into the understory and replaced the buckthorn.

I did not find the weed wrench helpful. For removal, I always waited until after a rain, because I could pull much larger plants out with less effort, and pulling out the plant and roots was the best method for removal. If I had to cut plants because of their size, I cut as close to the ground as possible and used a household spray bottle to apply a 30:60 mixture of concentrated Round-Up and water.

More Commentary on Buckthorn

I've been dealing with Buckthorn for 11 years and on an acre of land that was thoroughly infested I'm down to saplings that pop up every year (every time soil is disturbed, even from spring thaw, you germinate another cluster of seeds). I can't boast about my methods: they take time and hard work. I have found that pulling works best (brute force, no wrench) after rainfall or after many days of drought, or even digging around the roots first and then pulling. Loppers are good, too, for diameters ranging toward 2 inches. For the bigger ones, a pruning saw or chain saw close to the ground makes much more sense than the tall stump idea, in my opinion, and then -- instead of spraying -- dribble full-strength herbicide of the Round-Up® type (trypclor) onto the top of the stump, especially around that cambium layer. Once upon a time they said you should drill little holes into the cambium followed by dribbled herbicide, but that was overkill except perhaps for the very biggest stumps. If you do get those runners (hydra) growing out of a dead trunk, scrape away the bark with a hatchet or saw blade and reapply the trypclor.

I have never had luck with herbicidal spraying. You kill leaves and the tree just regenerates new leaves, but the tree itself (mine, anyway) won't die.

In terms of strategies for species survival, Buckthorn is an extraordinarily impressive plant: if only some of our more vulnerable trees had that skill set. I have read from other botanical material that the seeds can be dormant for up to 25 years (not just 7) and that they are still as much as 85% viable at 25 years. My house was surrounded by Buckthorn for 30 years, invasively killing everything else on the forest floor before I started eradicating it, so there are thousands of seeds waiting to germinate every year. The "war" metaphor is pretty accurate; be willing to realize you're dealing with guerrillas that will be back where you have already been. Good luck!

Ron...

An entertaining, as well as informative, article......thank you.!

buckthorn removal

Our best results in removing sucker stumps and small stalks/trunks is with a pick axe that has an adz tine on it approx. 4 inches wide.

Undermine the root ball with the adz tine and tilt the handle to uproot the stalk and root ball. shake the root ball clean and dispose of the rest.

this works quite well for up to 3/4 to 1 inch depending on your strength. you may need multiple swings and work in a 360 degree circumference for the larger root balls.

for larger diameters we have good luck using an atv and chain and the gripper tool purchased at Northern Tool and Equipment. the tool has teeth on both sides and tightens down on the stalk as the chain gets tighter and tighter. this will dispense of trunks from 3/4 to 4 inches depending on the strength of your chain and ATV.

Spring and Fall or right after serious amounts of rain seem to be best times as those root balls with fine hair-like roots are quite tenacious in drier weather.

Remember, to be deliberate and don't overdue it and hurt yourself. The buckthorn is not going away it will be there tomorrow. Better to take it slow, do a good job uprooting and yanking the stuff vs. cutting and using herbicides. get a cover going ASAP so as to offer competition vs. the buckthorn that is invariably lying in the soil just waiting to regerminate.

good luck!