In the 1500's
California went through an 80 year drought. During the winter there
were blizzards in Central California, the Salinas river froze solid
where it flowed into the Monterey Bay. During the summer there was no
humidity, no rain, and temperatures in the hundreds for many
months. During one year in the 1840's there was no measurable rain in
Santa Barbara. (The highest measured rainfall in an hour also was in
Southern California, 11 inches in an hour) The same native
plants that lived through that are still on
the hillsides of California. California native plants that do not
normally live in the creeks and ponds are very drought
The best way to find your plant is to check www.mynativeplants.com and do not water at all. But if you want a simple list of drought tolerant plants that can work for your garden here are some for the Los Angeles Basin.
If you want to see what you're missing in the Los Angeles area, find an early 1940's Republic western like Sheriff of Sundown, with Allan Lane. They were largely filmed in Chatsworth. By the 1950's you could see the weeds had replaced much of the vegetation.