Buckthorns of the genus (Rhamnus) are an invasive noxious species from eastern Europe and Asia. They grow prolifically throughout much of the northern states. They are the last trees to lose their leaves in the fall, so non-native plant enthusiasts are typically pleased to see that bit of green before the snow begins to fall.
BUT, buckthorns are one of the biggest factors in the desecration of our woodland habitat.
Their root systems are dense and shallow, so they use up all the nourishment in the surrounding area and prevent other plants — native or otherwise — from growing in their understory. Their berries can lay dormant in the ground for up to 7 years producing more new seedling buckthorns whenever conditions are right.
Buckthorn, Birds & Diarrhea — although there is some disagreement regarding the effect of buckthorn berries on the guts of insects and birds, it is generally thought most are not able to break down the metabolite known as anthroquinone. If not broken down, anthroquinone produces emodin, a cathartic which causes diarrhea and often leads to dehydration and then death of the insect or bird. If a bird manages to survive eating the berry, it of course poops out the seed in some other habitable location and a new invasive noxious buckthorn is allowed to germinate and grow.
Eradicating buckthorn is not a fast undertaking. Tackle the largest specimens — the ones that are producing black berries – first. I have found cutting and painting the stem of the larger trees with 50% concentrated Poison Ivy Roundup works pretty effectively. Note: You must paint the cut end immediately after cutting down the tree; before the sap starts to cover the wound. Fall is the most effective time to cut and paint — when the tree is pulling all the nutrients down into its roots for winter dormancy.
Pulling small seedlings is easy, but often counter-productive because one simply exposes dormant seeds to sunshine and moisture, producing the perfect conditions for a new seedling to germinate.
Girdling large trees works pretty well also. In the late spring, after the nourishment has moved from the roots to the branches and the leaves, cut carefully around the base of the tree. Once it has no way to get nourishment back and forth between the branches and the roots, it will begin to die. Girdling too early in the spring, however, will simply allow the tree to form suckers.
So, it’s time to think about tackling the buckthorn in your yard. Think of it as good exercise! And don’t forget to plant a native tree or shrub or some native plants in its place. Here’s a fact sheet which includes suggested alternatives for you to think about. Have fun!
To purchase a Wild Ones Die, Buckthorn Scum t-shirt.
For more information about a variety of non-native invasive plants