Hmm. I didn't think about this & I hate using regular RoundUp or other chemicals with my roses. Do you think using straight vinegar in a jar & sticking a trailing vine of the weed (in my case, Bindweed) into the jar would do the trick? Bindweed drinks RoundUp like KoolAid & is impossible to kill by pulling. All you need to do is leave a 1/4" of a root behind & you got a new plant. I don't qualify for the insects that the CO Dept of Ag gives to farmers/ranchers to get rid of bindweed.. my yard is too small. And Bindweed doesn't seem to do too much damage to my roses. I just don't like having weeds everywhere. LOL