When we were removing the Ant Tree, I noticed that we were being invaded! Apparently buckthorn is not just isolated in Southern Ontario. We have scads of them!
I yanked out about 100 of the smallish ones after the rain and chopped down another 25 big ones even though I know that they will come right back up from the trunk. Just like any invasive species, they are hardy here.
Sadly, we have both the common as well as the glossy leaf. Even more sadly is that they still allow these to be sold at nurseries. Like most invasive species, these plants take hold and choke out indigenous plants.
Here is a photo.
Tiny House Ontario 