(Black?) Locus tree how to poison the stump?

[Fanatical Meat]

They are the large weird bark tree with sharp thorns and also sprout from the roots. They are asshole trees imo
They are invasive trees in Mass, we had two one of which we had cut down and that f’er kept sprouting from the stump which it appears has finally slowed to a crawl it has been years since we had it cut.
There is a second one in the neighbors yard which I don’t want to pay to remove because it’s a bigger job. This one has sprouted another nearby in my yard and for whatever reason I haven’t noticed it, probably because it sprout inside a bush.
Currently it’s trunk is about 1 1/2 inches. How do I treat the small trunk so it doesn’t sprout new growth like the stump did?
Should I treat the cut with concentrated roundup and be careful not to expose the bush it’s in?

 

[BoomerD]

Drill holes in it as far as possible. Fill them with RoundUp or another herbicide specific to the variety. I've used Crossbow and Cornerstone Plus for various woody shrubs...may work for locust. You'll have to do research.

 

[lxskllr]

I really like black locust. It's a pioneer species, and fairly aggressive. The problem is the sprawling root system. You aren't dealing with a tree per se. it's more a colony. If it were me, I'd just cut the limbs off as they sprout. You're gonna have trees coming up regardless of what you do, so you might as well forego the chemicals on that particular sprout.

 

[turtile]

They are the large weird bark tree with sharp thorns and also sprout from the roots. They are asshole trees imo
They are invasive trees in Mass, we had two one of which we had cut down and that f’er kept sprouting from the stump which it appears has finally slowed to a crawl it has been years since we had it cut.
There is a second one in the neighbors yard which I don’t want to pay to remove because it’s a bigger job. This one has sprouted another nearby in my yard and for whatever reason I haven’t noticed it, probably because it sprout inside a bush.
Currently it’s trunk is about 1 1/2 inches. How do I treat the small trunk so it doesn’t sprout new growth like the stump did?
Should I treat the cut with concentrated roundup and be careful not to expose the bush it’s in?

Garlon works great and you can simply paint around the bark at the base with the concentrate. The downside is that it's sold in 2.5 gal containers. You could use Roundup as well but most store concentrates are lower than the true professional version. It's very likely that you will still get resprouts but the herbicide will greatly damage the plant's ability to regenerate since the chemical moves into the roots.

 

[Gardener]

Recut the stump to expose fresh wood, paint the cut with concentrated roundup, slip a plastic bag over it, fasten it, done.

You generally get a very interesting reaction after a few days, different than just normal cut weep, showing strongest at the cambium layer.

 

[Mermaidman]

Drill holes in it as far as possible. Fill them with RoundUp or another herbicide specific to the variety. I've used Crossbow and Cornerstone Plus for various woody shrubs...may work for locust. You'll have to do research.

And do it a few weeks before you cut down the tree. After it dies, then cut it down.