Category Archives: invasive plants


Why aren’t desirable plants as hardy and prolific as the dreadful tree-of-heaven? (ailanthus altissima, also called Chinese sumac or stinking sumac)

A large, unattractive tree grew in the back of our garden. Until 5 years ago, I didn’t know its name and didn’t care. Our next door neighbor called it “railroad trash” and volunteered to cut it down in February of 2007. Seedlings from the tree were sprouting constantly in their back lawn, he said. I didn’t notice seedlings in our gardens, but I wasn’t paying much attention at the time.  We did find small saplings occasionally.  Bianca had told us they were black walnuts.  That might have been the only time she was wrong about a plant.  (Black walnut and tree-of-heaven are frequently mistaken for each other.)

Tree-of-heaven sucker (image from UMass).

Within weeks of Bob’s felling the tree, sticky little suckers began appearing everywhere, some as far as 50 feet from the stump. Who knew the tree would go into a defensive posture upon being harmed?

In just a few months, a thicket had grown around the stump of that tree, with saplings ranging in height from 6 inches to 8 feet. I pulled at the smaller ones, breaking off many of them just below the surface … they have long, stubborn tap roots. More suckers grew in their place. I sprayed them all with a powerful herbicide. Their leaves drooped, but they survived. Nearby mock orange shrubs weren’t so lucky.

Tree-of-heaven sapling (image from NCSU)

Thank goodness for Google. Typing the phrase “kill tree-of-heaven” revealed the best method for destroying it: hack-and-squirt. With an ax I made downward angled slashes about 2 feet off the ground into the cambium layer of the mother tree (well past the bark), leaving an inch between the marks, until the trunk was encircled. Wearing rubber gloves, I sprayed concentrated herbicide into the slashes.

It worked. Suckers began to die. New ones stopped appearing. Bob used his chainsaw to slice a disk off the stump, and I painted the fresh-cut surface immediately with the herbicide. I also hacked-and-squirted two smaller trees-of-heaven nearby, and they died quickly.

The stump of the Mother tree has since rotted.  One of the smaller trees fell a year or two ago, and the other just needs a good push away from the pine it’s leaning against. Then the trees-of-hell will be out of our garden forever. I hope.

Seeing them alongside a highway still makes me recoil.