I'm, going to experiment with dousing cut buckthorn stumps immediately with industrial-strength vinegar. I'm using 45% acetic acid straight. I also use this product 1:2 with water in replacement of glyphosate and it works great, at least at the scale I need it for, for general weed control. You just have to be careful as it is non-selective and will kill anything green. Will it work on buckthorn stumps...tbd.