Battling Buckthorn: The Search for New Techniques – NH News
by Phil Price, John Stevens, Chuck Curtis, & Zeb Campbell
Glossy Buckthorn and Common Buckthorn are non-native tree species that were introduced from Europe as ornamental plants. Buckthorn leaves and berries are toxic to most animals, and buckthorn emits chemicals that inhibit the growth of other plants. As a result, buckthorn creates dense stands that few other plants and animals can use. Buckthorn is having a severe impact on North Haven, especially (so far) on the northern half of the island, so many year-round and summer residents are trying to control it. Here are some of their stories. (For longer versions, visit nhwebb.org).
John Stevens:
One of North Haven Conservation Partners (NHCP) land management goals is to maintain and improve the ecological health and biological diversity of the lands in its care, including controlling invasive species. Controlling the growth and spread of glossy buckthorn is the biggest management challenge NHCP faces. NHCP is implementing a variety of techniques. One of the first steps NHCP took was to enroll in the State of Maine’s Invasive Species Plant Management Program, which provides partial funding for the development of an Invasive Species Management Plan for each enrolled property. The plans outline practices to control invasive species on a parcel of land and provides partial funding for implementing the plan. This program is open to any landowner with at least 10 acres and provides technical advice and some funding to control invasives on private land. Practices include: mechanical (cutting/pulling); targeted herbicide use; planting native trees; and mowing infested fields multiple times during a single growing season. Some areas, such as a birch grove on the North Shore Preserve, require the buckthorn to be cut annually. Buckthorn near young native trees is cut. Large trunks are cut at chest height, multiple times over a period of years, until the plant dies. In 2024, thanks to the help of many volunteers and the Maine Conservation Corps we were able to treat nearly 9 acres of woodland, roughly 20 acres of field were mowed twice and 250 trees were planted.
Chuck Curtis:
As a tromper of the woods and Park Commissioner, I have become very aware of the Buckthorn problem on the island. At Mullin’s Head Park I have been geolocating buckthorn trees and infestations. I focus on pioneer trees: trees that are mostly mature and fruit-bearing, and are the extension of infestations. This past summer I cut off the upper story of nearly 100 pioneer trees to prevent the fruit from ripening. This fall as the roots are storing sugar for the winter, I recut the 3-4 ft. stumps to the ground, and immediately treated the cambium layer of the stump with a tiny amount of herbicide with blue dye. The dye allows me to see what has been spotted in and helps to prevent over treating. I wouldn’t use this method with an infestation as it would require too much herbicide in a small area. To date I feel confident I have killed well over 200 Buckthorn trees in the Park, during the past two years, and on Burnt Island last year. Taking care of a property before the Buckthorn gets too established is an easy way of slowing its spread.
Zeb Campbell:
When my partner Edith and I purchased our two acres on West District road in December of last year, I spent the entire winter cutting buckthorn at the base of all the trunks. For about two months, I piled up the cut buckthorn, and burned it.
One night after a long day of burning buckthorn I read a section of the book The Holistic Orchard, by Ken Phillips, where he recommends mulching around fruit trees using wood chips that come from only small diameter trees and branches . I began chipping every single buckthorn tree I cut down then spread the chips about 6 inches deep in a 3 foot ring around each of the peach trees I had just planted. Fast forward 4 months to the Common Ground Fair where you can bring soil samples and get them tested for free, courtesy of the University of Maine. I took in a sample from directly under the ring of buckthorn mulch. Upon testing it, the man exclaimed “Where did you get this!?” He said it was the most active sample he had seen all weekend (that’s a good thing!).
Next time you’re out doing your buckthorn cutting or pulling, chip it, and spread it around, your soil will thank you.