Killing Trees That Sprout From the Roots

All It Takes Is Patience, Herbicide (optional) and a Shovel

Black locust, (Robinia pseudoacacia),  Tree of Heaven, (Ailanthus altissima), and a few other shrubs and trees are notorious for coming back from the roots if you cut the main plant. In the wild they make large thickets, in the landscape they make a mess.

We removed a cluster of volunteer Ailanthus trees because they were wrecking the fence, endangering the neighbor's power lines and providing too much shade on the flower bed.

The First Attempt: Because I had heard horror stories about how hard these are to kill, I went 100% forest service style for removing them.  It involves hacking into the trunks with a hatchet and promptly applying glyphosate to the cuts at the "right time of year" to translocate the herbicide for an efficient kill.

It worked, they died that summer, and I had someone remove the trees down to stump level.  They are currently hidden by flowers, quietly rotting away and sprouting many inedible mushrooms. 

Ailanthus Stumps

NOTE: Ailanthus is a dense wood with good burning qualities.  The stale peanut butter smell of the green shoots and leaves is not in seasoned firewood.

But ... their roots sent up an army of sprouts all over my yard and the neighbor's yard in a desperate attempt to survive.  Despite my meticulous killing technique, I spent almost a full year yanking out and spraying sprouts. 

Sprouts of Ailanthus

The Lazy Way: A black locust was removed because it shaded the only good place we have to grow chile peppers. We skipped the hatchet preliminaries and just had the tree chainsawed to the ground.  It regrew a cluster of sprouts from the base, as expected. Glyphosate killed them, as expected. 

Black locust sprouts erupted all over the yard, as expected.  They are weakly attached to the root and easy to pull off.

Root Sprouts of Black Locust

Every time I see sprout cluster emerging, I pull the sprouts out of the ground.  If the area is accessible, I dig to locate the root and cut out the chunk that is sprouting. 

Conclusion

It doesn't appear to matter whether you kill the trees first.  You will have sprouts to deal with, so skip the fancy stuff and get the trees out quickly. Patrol the entire yard for sprouts for at least two growing seasons and pull them as soon as you see them. Eventually even Ailanthus can't sprout more because the roots have exhausted their stored energy.