While it might be fun to go native, you have to ask, how native? Here, a purist would only use natives to El Dorado County, on the west slope of The Sierra Nevada Mountains. Wait; are they on an outcrop of serpentine, or granite, or red clay? Very different species grow in these three soil types, all in El Dorado County.
Going completely native might be a fun horticultural pursuit, but I feel that you have to broaden your horizons to create a "garden." People here seem to use the word "native" to describe any plant from California. Considering our state has some of the most diverse climatic regions of any area, I don't see how a native plant from southern California, on the coast, fits our region, as a native.
Non-Native Grevillea "Penola".
So, it's really a case of semantics. What does native mean? Lets leave that to the purists. I think if you are trying to save water, or maintenance time, you are better off planting a xeriscape garden. There is a wealth of plants from other Mediterranean climates that use low water and require minimal maintenance. Many plants from Australia, South Africa, The Mediterranean region, or Chile meet these requirements.
A true "native" "garden' is difficult to come by, but by mixing natives and other xeriscape plants together, you can create a more satifiying effect, while still conserving time and water.