Hi Moxie and
to the maddness of the Semp forum!
You've had some great answers to your questions, so I don't really have anything to add, just a warning: You be careful of these guys. I arrived in Febuary looking for a bit of advice on how to plant some semp seeds, and how best to look after a few common houseleeks that my Grandad used to grow. 3 months on I've had to dig up a good size chunk of my garden to accomodate my ever growing collection, as well as a load of large conatiners!