For bearded irises: full sun (min. 6 hours/day), good drainage, don't need a lot of water. However, in zone 10, the dwarf irises won't be very happy - they like some cold in the winter. Same with Siberians. But I know people grow tall beardeds there successfully. Some reblooming irises can be almost ever-blooming in the warmer zones, too. IIRC, someone not far from you reported 'Lo Ho Silver' with bloomstalks every month of the year!

Ohhhh, yes. You can grow irises in San Diego.
If you are looking for lots of bloom, try reblooming varieties. Also be sure to try to find pictures of clumps of irises in gardens to get the full effect: sometimes they look spectacular as a single flower but disappoint in a garden. I recommend Total Recall and Frequent Flyer for blooms from late March to November in your area. Both go beautifully with most colors in the garden.