Hardy plants are not my specialty living in so. cal. I'd suggest asking at the local garden center. I like Oriental poppies and Toad lillies (Tricyrtus). It depends on your exposure (sun/shade) and pot size. Wisteria may be a good choice if you have a big enough pot. You may want to check out these links:
http://www.burkesbackyard.com.au/200..._sun_and_shade
http://www.bbg.org/gar2/topics/desig...wintering.html