I let vinca minor get way out of control(all around the house, front,back, sides, and spreading into the woods. I'd like to get rid of most of it so I can use that space. It's way to much to pull up, and that doesn't seem to work. It comes back. I've been spraying it with 20% vinegar and using the weed torch. That also takes a long time and I have to do it repeatedly so the roots die. Does anyone have a suggestion.