Will this stuff kill neighboring trees and such?
I have a fenced area full of various flowering bushes and roses. It was overgrown with weed trees and vines due to laziness. The Tordon killed one bush and a rose but most of the good stuff was fine. And a patch of rhubarb plants that was overrun too. All the weed trees died but the rhubarb was fine. It can spread to nearby roots but not very much. You paint it on the stumps rather than spraying it.
I used it on weed trees and vines that were growing around the base of larger trees and the trees were unaffected. To have an effect on larger trees you have to drill holes in the sides near the base and pour in large quantities of the stuff. Or cut them down and treat the top of the stump. The tiny amount that gets down into the roots of weed trees and vines will sometimes affect small stuff with roots that are in contact.
I worry about dogs though. I killed a few stumps in their area but covered them in pieces of tarp held down with rocks for the winter.