Fighting invasive tree-of-heaven

This summer, I’ve been battling tree-of-heaven (Ailanthus altissima) like never before. We’ve written before about this struggle, but I’ve never seen it keep coming back so aggressively from the root – till now.

Ailanthus is an alien species (read more about it in our previous post), that has become a regular citizen of Toronto’s unguarded laneways and unclaimed lots. It’s also a problem in our city parks. The High Park Nature website explains my current problem this way:

Due to the rhizomatic spreading, root suckers often form groves or thickets and persist for up to centuries while providing a seed source for nearby disturbed areas.

And here’s a closer look at what that means to you and me.

Every one of those white suckers can grow into a trunk, giving you an instant thicket of tree-of-heaven that reaches the sky.

My fault. I didn’t get out all of the root at my first weeding of this particular seedling, and the picture above shows the result below ground. Here’s what it might look like on top. Each tiny shoot is tender, and can break when you pull, leaving that prolific root behind. This year has made this sad fact very clear to me!

All these shoots probably grow from the same root, and are best dug out rather than pulled.

If you see tree-of-heaven starting to emerge, get out a trowel, shovel or Cobrahead and get out all the root if possible to avoid problems later! Take it from me.


  1. I feel your pain. At my last home and garden I too had a problem…biggest problem was I didn’t know what it was until too late. It flowered and I had seeds/trees growing everywhere with a couple of years. I had one that grew into my home’s rock foundation. A seed implanted itself between a cement rain barrier and the foundation. To say that it took dynamite to get rid of it would be a tall tale but not too much of an exaggeration. I had to use a very potent herbicide that I painted on the bark in order to kill it. Hated to do it but it was the plant or the house.

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