You could try checking out Las Pilitas Nursery ( http://www.laspilitas.com/ ); it has quite an extensive database for native plants--including a native plant "finder" that will find something that suits your situation (though planting in proximity to the lawn might pose some issues from competition for nutrients). My personal favorites for California native plants are (as my ID indicates) Manzanitas (which aren't quite suitable to be placed nearby the lawn), California Fuchsias (these can be planted closer to the lawn if you want), Monkeyflowers (Mimulus guttatus can live nearby the lawn, being that it lives in riparian habitats in the wild), and Sages (there's so many aromatic sages in California, with some species capable of tolerating more water). California has quite diverse climate that produces various natives suitable for a multitude of environments; there's probably something that can work for you. This post was edited by CAManzanita on Mon, Sep 2, 13 at 19:21

Not the easiest species to grow, very sensitive to phythopthera infection. I'd suggest the similar looking Heteromeles arbutifolia instead, or non-natives such as Tristania laurina 'Elegant' or Metrosideros collina 'Springfire' as good, drought tolerant, small trees, or Acacia cognata if you are okay with 25~30 feet tall by across.

My favorite native plant that I have growing in my garden in my false rosemary/scrub mint. It's drought tolerant, extremely hardy, blooms nearly year round, and the foliage has a wonderful fragrance when it's brushed up against. It also grows so thick that no weeds are able to grow through it. The only trouble is that is attracts a lot of bees so if you're allergic to bees I wouldn't plant this near a pathway or gate. I happen to like seeing all the bees that visit the plant. Altough scrub mints like full sun mine is planted under a crape myrtle tree and is thriving. This is a close up of the flowers. Another tough, drought tolerant native that would do well in the conditions you described is the wild petunia. You could also try beach sunflowers although they seem to prefer as much sun as possible.

Caesalpina gillesii (shrubby but can be trained as small tree) Arbutus unedo Acacia aneura Olea europea 'Wilsonii' (fruitless olive) one of the larger growing ceanothus ('Gloire de Versaille', 'Ray Hartman', Gentian Plume' - all kind of shrubby but easily trainable into a tree form. None should need any supplemental irrigation once established but establishment takes time. I would agree with the above that now is not likely a very good time to plant. And being stingy with irrigation tends to limit or slow growth as well, so all should remain around 20' or less. And there is nothing particularly drought tolerant about anything in the Prunus genus, so skip the flowering plum. And even ornamental or flowering plums and cherries (and pears) can produce fruit. There are none that are entirely fruitless all the time.