Meant to tell you, I sprinkle some granulated gypsum in and around the flowerbeds, esp. for the Agastaches, because they need (like Lavenders, Salvias and Penstemons) a well drained soil and they don't like 'wet feet' (if you know what I mean). I always try and give my plants very well drained soil to be on the safe side, but I don't seem to always exceed.
I've been ordering from HCG since Spring 2005, but I envy that you can get their plants locally.