Creating a landscape of local native plants is the ultimate way of sustainable landscape gardening. You will be surprised at the wildlife that enters your garden. You will use a lot less water, have less pests, and less work. But a native landscape needs to be thoughtfully planned. Just because a plant is a California native does not mean it will thrive in your area. California has very diverse climates throughout the state, and even within several miles! To find the most appropriate native species for your area, use the California Native Plant Society's CalScapes tool, or use the resources provided by Rancho Santa Ana Botanic Garden. An excellent book on landscaping with native plants is by Greg Rubin and Lucy Warren - The California Native Landscape: The Homeowner's Design Guide to Restoring its Natural Beauty and Balance.
If you are going to use California native plants ("natives") in your landscape, consider their water needs versus the water needs of the rest of your landscape. Natives that are local to the Inland Empire are adapted to surviving in a climate of low rainfall and no summer rain. Local natives are used to shutting down for the summer. If you water them regularly throughout the year, as in a Mediterranean or temperate climate garden, they will rot and die. However, if you use a native that originates from a riparian area (wet area), you will likely not kill it with summer watering. As you can see it is imperative that you know the origin, or seasonal water needs, of your native plant species so they can be planted with plants of the same water needs.
The care and maintenance of native plants is different than what most people are used to. Most native plant species have two periods where their growth is greatly slowed: summer and winter. Therefore, the best time to prune natives is at the end of summer and the end of winter. Why? Pruning stimulates new growth. If you prune during the hottest part of summer or the dead of winter, you are forcing the plant to push out new growth when the plant is trying to hold on to its reserves of water (in the summer), or not have new tender growth freeze (in the winter).