Tackling Buckthorn in the garden
Why Buckthorn is a dangerous invasive in our woodland gardens
If you’re not paying attention, Common Buckthorn can creep up on you and devour areas of your garden.
It’s not going to happen overnight, but if you have a neglected area of your garden you have let go wild, watch out.
In a few short years Buckthorn can take hold and begin the takeover.
Thankfully, getting rid of it is easier than you may think.
What I thought would be a multi-year restoration project turned out to be a relatively simple one involving a few days of work yanking out the (two-to-three-foot-high) woody plants.
These images show mature Buckthorns in late summer with the blue-black berries that birds eat and help to spread this non-native, invasive shrub or small tree.
How Buckthorn takes root
It all began shortly after we moved into our home more than 25 years ago.
Our neighbour asked me over to identify a large shrub or small tree that he had been cultivating in an area of his back garden. I immediately recognized it as a Buckthorn but thought little of it at the time.
Thankfully, that Buckthorn tree is long gone.
I suspect, however, its offspring have spread far and wide and hundreds made their way to an area of our garden that I had let go wild.
A large berm across the back of our garden under two large crabapples proved to be the perfect place for birds to drop the berry seeds and begin growing a small forest of invasive Buckthorn. A few grew to an impressive size – large enough to spread their own seeds – and the invasion had begun.
As long as I was mowing the grass on the berm on a weekly basis, it was not a problem. Once I stopped, however, the buckthorn was allowed to grow wild.
Several years ago, I attacked them with a gas-powered brush cutter that made the area look under control but, in reality, only masked the problem.
A degenerating hip made gardening more and more difficult and meant the Buckthorn took root. That all changed this spring when a hip replacement made it possible to finally tackle the forest of Buckthorn.
What I thought would be a multi-year restoration project turned out to be a relatively simple one involving a few days of work yanking out the (two- to three-foot-high) woody plants.
I need to add that our very sandy soil made the task a whole lot easier. The smaller shrubs (2-3 feet high) (1 meter) came out root and all with just a good hard tug. Larger trees in the 4- to 6-foot range (1.5 meters) needed to be rocked back and forth for a minute or two before the soil was loose enough to pull the small trees out with roots. A few larger trees had to be cut off with a chain saw at waist height. My plan is to block out all sun with plastic bags to slowly kill these last two larger trees.
Years of maintenance ahead
I first tackled a 15- to 20-foot section between the two crabapples. To my surprise, the small shrubs complete with roots came out of our sandy soil with relative ease.
A visit from a gardening crew – including two strong young fellas – resulted in a one-day elimination of our Buckthorn problem. Even larger, 6- to 10-foot trees (3 meters) were easily removed with a little rocking back and forth to loosen the roots.
That’s not to say that the Buckthorn is gone. Years of maintenance will be required to keep them at bay, but the hard work turned out to be much easier than I expected and we are well on our way to eliminating the problem.
Buckthorn’s range in the United States and Canada
Common buckthorn (also known as European buckthorn) is native to Eurasia. Introduced to North America in the 1880s as an ornamental shrub and used for fencerows in agricultural areas.
Since then, this spiny shrub or small tree has spread aggressively into wild areas including gardens where birds have dropped the seed.
Common buckthorn is found throughout the northeastern United States into the north central regions of the United States. In Canada, it is found throughout Ontario and as far west as Saskatchewan and east to Nova Scotia where it thrives in a range of soil and light conditions.
It can be found growing in woodlands and open fields where its dense stands shade out native plants. Large stands of Common Buckthorn have invaded roadsides, hydro corridors as well as damp riverbanks, forests and open agricultural areas.
Why eliminate common buckthorn
Buckthorn creates dense stands that shade out our important native plants and shrubs. It can also alter the soil’s nitrogen levels further inhabiting native plants.
It spreads quickly by producing an abundance of seeds that quickly germinate.
It can affect agricultural crops in a number of ways by hosting a rust that affects oats and an aphid.
Identifying common buckthorn
Buckthorn is among the first to leaf out in spring and the last to drop its leaves late in the fall.
The flowers of Buckthorn have two to six small yellowish-to-green petals.
It has smooth, dark green leaves that are finely toothed, about 2-inches long (2.5 to six centimetres long), and arranged in opposing pairs along the stem.
Buckthorn carries short, sharp thorns toward the ends of its branches.
It often grows two to three metres tall, but can grow up to six metres, (19 feet) with a trunk up to 25 centimetres (19 inches) in diameter.
One of the most telling identifiers are the clusters of berry-like black fruit that appear in late summer and fall and are attractive to any bird species.
Common buckthorn resembles another invasive species, glossy buckthorn (Frangula alnus), and a much smaller native shrub, alder-leafed buckthorn (Rhamnus alnifolia).