If at first you don’t succeed, kill, kill again

If you don’t succeed the first time you try to kill those little green monsters, don’t take it personally. Hardly anyone finishes the job on their first try, and most people discover that death is surprisingly difficult to impart. The important thing to remember is that we’re all in this together. There are resources out there to help you, and by golly, I just know that the next time you go on a killing
spree, you’re going to get things done.

Let’s start by reviewing the events leading up to today. You were walking in your backyard woods a few years ago and noticed that the understory had become an impenetrable fortress of thorny shrubs with smooth, dark green leaves and small, round, purple berries. Or, maybe it started when you bought your new home two years ago and decided to plant native woodland flowers and trees along the back edge of your property to spice up the view a bit and improve wildlife habitat. Soon thereafter you talked to a neighbor or friend who gave you the news no one wants to hear, “You have buckthorn.”

Buckthorn is an aggressive, invasive shrub that hails from Europe. In its homeland, it is just one of many plants that form a rich mosaic of woodland vegetation. Here in the U.S., however, it is more like a viral disease. Buckthorn spreads quickly through Minnesota woodlands, taking over the understory, and choking out native flowers and shrubs that provide food and habitat for birds and wildlife. It also prevents saplings from taking root and growing, making it a long term threat for oaks, maples and other hardwood trees.

Because it shades out groundcover plants, buckthorn causes water pollution as well. Rain quickly washes exposed soil under the
buckthorn into nearby water bodies, and continual erosion causes lakeshores and streambanks to slump and ravines to form in bluffs along the St. Croix and Mississippi Rivers.

Like many others who learn that they have buckthorn, you were quick to act. You began attacking with bow saw and herbicide and at first it appeared that you were winning the war. When spring arrived, however, the dead stumps resprouted with ten times as many branches and a carpet of baby buckthorn emerged from the melting snow. Understandably, you grew frustrated and discouraged and now, more than ever, you need advice and support to continue on your mission of death.

Unfortunately, there is no easy method for buckthorn control. Management is labor intensive and usually requires at least some
herbicide use. There are, however, several killing techniques that have been proven to be effective over time. To begin with, know that buckthorn is an extremely hardy opponent. If you cut it down, you must apply herbicide to the stump within an hour or else it will resprout and live on. An over-the-counter herbicide like Round-up is not very effective at killing woody plants like buckthorn, so you might need to purchase a stronger herbicide like Garlon. If you are really opposed to using chemicals, try putting tin cans over the cut stumps to keep them from regrowing. Pulling the entire shrub and root mass from the ground with a weed wrench is also effective, although impractical for more than a small area. For large stands of buckthorn, try girdling the trees with herbicide or using a newly developed tool called the hypo-hatchet (see www.forestry-suppliers.com for more info), which dispenses herbicide into each buckthorn plant you whack, allowing you to move quickly through a grove, killing with abandon. In both cases, the trees will continue to stand for one to three years, until they eventually die completely and fall down.

Here I am, killing babies at the annual Newport Community Buckthorn Pull. Fall is one of the best times of year to pull buckthorn because it retains its green leaves longer than other shrubs, making it easy to identify.

Regardless of how you kill the adult buckthorn shrubs, you will likely be shocked by the number of offspring that come back for revenge the next year. Don’t be fooled by their small stature and innocent appearance; within months of emerging, they will already be too tough to pull by hand. Depending on the size of the area you are tackling, you can either pull the shoots from the ground as soon as they emerge, use a mower to cut them down several times during the growing season, or spray them with herbicide. Be
forwarned that it will be three to four years before new shoots finally stop emerging. In the meantime, you can help to restore the health of your woodland by planting native flowers and shrubs in the understory so that buckthorn saplings find fewer places to invade.

Visit www.mnwcd.org/buckthorn to learn more about managing buckthorn on your land, including removal strategies, information about controlling buckthorn with herbicides, and a list of local buckthorn consultants that can help you get the work done.  Remember, if at first you don’t succeed, kill, kill again.