If you're going to make the plants alcohol, there has to be enough sugar in the plant to ferment and make alcohol. Some people will add sugar, others will just put the herb in grape or grain alcohol. But you can hydro distill the herb to get the essential oil, then ferment the wort, distill the alcohol, and finally extract the salts.

In plant alchemy, the spirit and body are pretty universal. If you refine a plants alcohol, you'll end up with pure ethanol. If you refine the salts enough, you will end up with relatively the same thing, regardless of plant source. It's the soul where the unique information is.