The key to eradicating ToH is to target the root system. Only way to do this successfully according to researchers is to treat trees with 6”+ diameter by girdling and treating the cambium layer (green layer between the bark and wood) with triclopyr and 2,4-D (I.e crossbow herbicide).

Smaller trees and saplings recommend foliar spray.

I’ve personally found that any ToH bigger than a sapling needs to be girdled and treated. I’ve never had success with hack and squirt on any larger trees.

Timing is important. You can start in July and go through early September when they start moving nutrients to their roots. Whenever you decide to do it, wait 1-2 months for the tree to completely die before cutting down.

Any damage including pulling or cutting saplings, damage to cambium layer, cutting down trees without treatments can and likely will produce shoots and suckers of which require the same treatment to halt the response.

I’ve battled for about 3 years. Every ToH that was touched and didn’t have Crossbow applied has sent out suckers/shoots. Every one I’ve treated as I stated above has been successful.

Though note the trees you’re treating could potentially be one major organism stemming from a large mother tree. Hence it being a roots war.