I have painted the "stumps" of many kinds of plants with straight glyphoshate, and none have ever re-sprouted. Holly is especially difficult, so I cut off the bush, painted it, covered the painted stump with some Saran-wrap, and covered it with dirt. It never sprouted back.
Learned the technique from an 85 year old woman- saw her in a blackberry patch, with clippers in one hand and a cup in the other. She'd clip a vine, then grab the vine with the clippers and dip the cut end in the cup (which held straight Roundup). She said (with a laugh) "It really works. And it's a good thing it does, because at my age, it was about as hard a work as I can manage". Have tried it on various plants, and it really does work.