For a rockrose, this one is large, possibly reaching 8'. Given the size of the buds, I'm expecting large white blooms. Apparently, it was cultivated right here in California by the early owners if Western Hills Nursery in Occidental. I'm looking forward to seeing it evolve in the garden.
Apparently, it can be grown throughout low elevations of California but also as far north as Portland.
San Marcos Growers, a wholesale nursery, has a thorough description here. Contact your local retailer to see if they can order it in for you.