Harold Roth is a leading authority on plant/herbal magic.In his last visit to Stirring the Cauldron, Harold share his book, The Witching Herbs, an in-depth exploration of 13 essential plants and herbs most closely associated with witchcraft--13 because it's the witching number and reflects the 13 months of the lunar calendar.. Roth is not only a successful gardener, but also a magician and scholar of the occult so this time around, we took the subject one step further and talked about plant magic in general and that made for another interesting and informative show.