Winter can be a slower time in the landscaping business with fewer outdoor projects due to weather constraints. But cold weather and frozen ground are the perfect working conditions to remove buckthorn from Vermont’s native landscape. What is buckthorn? Where did it come from? Why should we remove buckthorn from our woodlands and landscapes?
Buckthorn, specifically common or European buckthorn, (Rhamnus cathartica) came to the United States from Eurasia in the 1800’s as a landscape plant for hedging. Lacking natural pathogens and pests in its new North American environment, the buckthorn quickly escaped the landscape and began overtaking native woodlands.
Common buckthorn grows to to a mature height of 20′-25′ tall. Buckthorn trunk diameter can grow up to about 10″ but most that we see in the Champlain Valley go from 1/2″ to 4.” Buckthorn has a glossy darker brown bark with noticeable lenticels. Lenticels look a little bit like dashed lines making rings on the tree. Older buckthorn has a rougher bark that may even peel a little bit like birch bark. Common buckthorn has a very distinctive orange color sapwood which is located right under the bark. With a simple scrape of a pruner or finger nail, you can easily make positive identification. In the fall buckthorn holds green leaves well after other trees are bare. Buckthorn trees tend to form dense tangled thickets crowding out light. This species is a very prolific seeder and produces tons of little black berry-like fruits on the female trees. Birds love eating the berries and readily spread the seeds with a little dose of fertilizer.
So why do we need to remove buckthorn from our Vermont woodlands? Buckthorn crowds out native understory plants. Buckthorn also crowds out successive species and can slow or stop natural forest succession. Imagine woodlands without sugar maples….. Forests that lack diversity of plants species soon begin to have lack of diversity in wildlife species as well. The dense thickets of buckthorn shade out forest floor wildflowers and perennials which are key to stabilizing forest soils and preventing erosion.
So back to winter and how to remove buckthorn. S & D Landscapes uses a technique that works with the native landscape and preserves soil integrity. First we go through the woods and identify all the saplings of native species “hidden” in the buckthorn we want to preserve. We then cut the buckthorn as close to the ground as possible and detangle the cut buckthorn thickets into piles. We use our mini skid steer with grapple to gently weave the piles through the woods without damaging other trees and saplings. The buckthorn is then chipped and the chips can be left on site as a mulch or we can haul them away for biomass fuel. As the cuts are still fresh we use an oil-carried systemic herbicide on the freshly cut stumps–application of this herbicide requires professional licensure. Why herbicide? The more “organic” option is to pull out the roots of the buckthorn. We do not like to do this as stump pulling activities can damage the roots of desirable native species. Pulling stumps loosens already fragile soil making erosion inevitable–further damaging native plants. And finally, turning over soil and exposing it to air and light unleashes the ENORMOUS seed bank of buckthorn seeds dropped over the last five years creating a resprouting situation capable of doubling or tripling the parent buckthorn density.
Buckthorn management doesn’t end with removal and cut-stump treatment. Nature abhors a vacuum and the buckthorn has a large seedbank. Ongoing treatment during the growing season of the small buckthorn sprouts will minimize future need of large scale buckthorn removal. It is also important to replenish the woodland with native species. S & D Landscapes can help you plan, select, and install a variety of native understory perennials, shrubs, and trees that will help restore and reclaim your native woodlot.