Posted: 27/06/2014 at 12:33
I don't think it is that powerful : )
It just releases some compounds that certain plants don't like, similar principle to many other types of companion planting. The only plants I have heard that don't like it are bindweed and ground elder, I would have thought that it would have being mentioned if there were common garden plants it affected in at least some if the articles ( and selling info) I have seen in this.
My sister is trialling it at the moment but having to restart as her slugs seem to be quite partial to it : /