I haven't irrigated my Southern California garden since September 2011. With the right combination of native as well non-native plants and loosing the lawn you don't have to waste a dwindling resource. As summer is now starting to take hold I'll deep water every 3 to 5 weeks from now through September.
It's crazy to think that you're only option for a drought tolerant garden in Southern California is cactus. I live in Agoura Hills which is an inland valley with average summer temps over 90 degrees.
I don't use pesticides or fertilizer. There's no need to when you maintain your garden in a natural state...which includes leaving a good amount of leaf litter on the ground. The decaying litter is a perfect habitat for beneficial insects that just happen to like eating destruction bugs. There are birds everywhere scratching through the leaves for a constant of food. With the right selection of plants you can have humming birds all year without having to clean another hummingbird feeder.
I get all of this with a little summer irrigation and minimal maintenance.
Pictures taken 7/1/12
Welcome to the jungle.
I like trails!
Plenty of shading spots for Betzi
The maintained area of my property goes about 40 feet up the hill and is criss crossed with trails that I built. What use to be a large lawn area many years ago is covered with mulch. About every two years I have my tree trimmer dump a load of chipped trimmings. Last year he had just cut down a cedar tree...it makes the best mulch and smells so good!