There are many and varied differences between Northern and Southern California. The difference I enjoyed the most on this visit to Southern Cal was seeing the plethora of Fan Palms, mostly, Washington Fan Palm which we have in Northern California, but it does not grow nearly as well or as prolifically.
In Santa Barbara they were especially pretty peaking through the coastal fog
Botanical Name: Washingtonia robusta, or filifera
Located on the coast in Santa Barbara, CA in USDA Hardiness Zone 10