What has been your experience using rubeweed to get the Luck of the Rube to increase gem drops? I was somewhat surprised (dismayed!) to find that shucking a rubeweed only produced one seed and that seed only produced two rubeweed plants. This seemed an awfully small return for the long trek to the community herb gardens. I only had Herbalism I at the time and have now finished H II, so maybe the return will be improved.
Anyway, I only used one weed for the buff while mining, needing to save the other one for more seed. (I know, I know, I can buy the stuff, but I have this pathological aversion to buying anything I can make/grow myself.) I can't say as I noticed any particular increase in gems while on the buff. Has it proved beneficial to you?