It's a legume. It would really help if we knew the location it's growing in. Definately not a tree of heaven/hell. Can you give a description of its flowers?

Honeylocust

The thorns on those trees are quite wicked. Of course if one has rubber or plastic skin they might not hurt as much! lol!

It is in Ukiah, California, Northern California about two hours away from SF and I think I have seen it listed as an invasive tree in my area. The reason I did not show you mine, is I keep it trimmed to the ground to discourage it. The lady who owned the house let it grow into a tree and it cracked the driveway, and I have to repave it, but its so expensive. I want be sure the roots are dead before repaving. But, three years have passed and no sign of it slowing down even. I even had the stump ground up, but it has these thick roots which are almost like concreate, and I can't plant new landscape shurbs because of the roots. I can plant only California poppies or things with new small roots system. It may be have caused even those poppies to be very small.

not many things die.. simply by pruning ...

you need to cut back the sprouts.. and treat them with a stump killer... and repeat this until you kill the whole root system left from the larger tree ...

as you have found out.. with no insult to that large root mass ... it can be very aggressive in trying to regrow..

ken

I looked up a stump killer product that was suggested to work on honeylocust, but then I checked "Tordon RTU how long stays in the soil" and I chickened out. I could get for only 20 dollars on amazon, but one of the reviews says it could stay in the soil and then migrate to other plants or trees via soil. I have other landscape plants somewhat near it. I wish I could find a stump killer that would not endanger nearby plants. There was something they used to sell, that was safe, but they don't sell that anymore.

Ask at an independent garden center.

I would just keep removing suckers manually. Safe, and a good exercise.

Lots of people "paint" the stump removed on the stump with a brush. The stump absorbs the chemicals, which then kills it. Usually not a lot of extra chemicals left in the soil because it's in the plant itself. Also more effective than pouring it over the plant. It's the same idea as baiting the ants to take the ant killer to their nest rather than spraying everything. I hope it goes away quickly and quietly.

What brand of stump killer, do you like Potassium nitrate or some other sort of chemical. I have been using round up on it for years, but that only slowed it down, even when I poured straight round up on it, it would stop growing for about a week or two and then get over it. We drilled some wholes in the bigger roots, but the little sprouts still come up even under the heavy gravel in another part.

I can't stand those trees. I've been ran clean through a foot, and the calf of my left leg. Took pliers to remove. We had a tree guy come out, and he ground the stump down to about 8 inches below the soil. Then he put the stump killer in. We covered it up. Had a few stray younglings to kill that first Spring, then nothing. It's been a few months since you put this up, maybe your troubles are gone. Big fan of stump grinders now.

I did have it stump ground, but like I said it comes back. I bought the really strong weed killer Tordon RTU . It was part my fault. I planted poppies near it and watered them.

I love poppies. I'm sure they were just beautiful! I'm really sorry about this tree. A line of them in a hedge row can be pretty, until mice decide to insulate your walls with the pod shells. I had a neighbor who had about 300 fancy mice escape, and they bred with the local population. These things were spread everywhere. Now I live in a condo. They've removed 2 from a hillside, but now they are just mowing the young. Our HOA does not want to spring for removal. Other than that, I have used a backhoe to ruin them. Dug around the roots, ripping through them with the bucket. Then I'd flip the stump, and bury it upside down, or added to bonfire. THAT was gratifying. Did the job, and how. We had a backhoe though. Probably a big expense.

It's in an area near the driveway and the roots are under the concrete. Tordon RTU is making some progress, but when the rains come it usually resprouts again. Much of the root is hiding under this driveway, if I could afford to I would get the whole thing ripped out, but its very expensive and it takes a permit to do something like that. I am sorry for the environment to have to use Tordon RTU .