Ranunculus can't freeze or it dies. It likes cool weather. It's an annual here 7a), and you plant it (in bloom, unless you have a greenhouse) in late march and rip it out when it starts looking miserable from the heat, usally late June/July.

Altadena and Sierra Madre get some chill - benefit of the mountains right behind them. A bigger problem for a lot of bulbs in So Cal is water - too much h water. After they die back post bloom, our warm weather added to water is a recipe for rot...