I would like to add that I have not tried this mixture but have tried using vinegar before with varying results. But that was JUST vinegar in water. Forgot to use a surfactant for starters, that is to say something like dish soap.
However, anything on the natural front must be better than using dangerous chemicals such as Round Up (glyphosate) which is but a cut-down version of Agent Orange (remember the stuff from Vietnam and what it did?).