This is a lively book with lots of information about sempervivums. These plants were a recent discovery for me---turns out they are the principal ingredient in green roofs. And enchanting small jewels if you look at them closely. In So Cal this species is not so easy to find in many varieties, but this nursery offers 262 different kinds. http://www.squawmountaingardens.com/
Keliadis says: "I don't admit to being a collector....once when shopping at a nursery offering 2,000 varieties (of sempervivums) I only bought 120 kinds."
Sempervivums are, as my astute readers already know, called hens and chicks. Esheverias are close relatives; we have lots of them available in So Cal. Sempervivums,being a lot smaller, don't get much recognition around here.(This is the land of Bigger is Better.)
The only semp available at local nurseries was s. calcareum ( see next photo). Now that global warming is bringing much colder weather to the Central Coast , frost proof is becoming an issue. These liliputians are not only frost-proof, they reproduce at the drop of--water. The one in the picture produced those chicks in a week. This means not only green roofs butgroundcovers that are cold hardy.
If you are an admitted plant addict like myself think of what a delirious project --- plant a parking strip with lots of varieties of groundcover semps under larger succulents. More about parking strips later.