What herbicide is best for killing The Trees of Heaven?

[Amateur Gardener]

I have the Trees of Heaven growing in my backyard and have found out that hack-and-squirt the trunks of the Tree Heaven is effective at killing it. But which type of herbicide is effective at killing the Trees of Heaven? I'm using Round-Up QuikPro but it hasn't been effective in killing it.

 

[Tetters]

A herbicide with glyphosate is best I think. This needs at least a month to work, and then it would be a good time to cut the trees down. The roots will need to be dug out ...... alternatively drill holes in the remaining roots and fill with epsom salts - cover and tie with black plastic to keep the light and rain out - this will take 12 months to rot the root. Seedlings, which will no doubt be plentiful (and quick growing) will need to be pulled out every time you see them and burned.
Good luck.