Locked In A Battle

I am in a battle with the buckthorn growing in my yard.  I attacked them yesterday.  Armed with a racheting pruner and a spray bottle of Round-Up, I attacked.  I prefer to pull them out by the roots.  If I can pull them out, they die without having to spray poison on my property.  I can pull buckthorn. I pulled buckthorn as tall as my armpit.  I tug and tug and can feel/hear their roots letting go and snapping.  But the buckthorn fights back.  I was so into pulling buckthorn yesterday afternoon that I didn't realize I was forming a giant blister on my right forefinger until it was too late.  I'll need at least a week of healing before I can pull buckthorn with my right hand again.  Tricky stuff that buckthorn.  Some trees are so large they have to be cut.  I cut the branch and the stump hides under leaves to avoid the squirt of Round-up.  Those that can be pulled resist me enough that my hamstrings are screaming today.  I'm not giving up.  I won't allow the buckthorn to win; not in this yard while I'm here.