I am extra careful anytime I use a "systemic" herbicide on our property.
I have treated hard-to-kill honey locust trees on my property, and had a very high kill rate on nearby trees where the root circumference of the treated tree just barely reached the root circumference of the distant tree.
I also work hard to keep that stuff out of my waterways when treating terrestrial plants. Who knows what kind of unintended kills that could produce.
However, when you need a systemic herbicide to do the job, you NEED a systemic herbicide!