Drought tolerant doesn't mean plant it and forget it. All plants need care and water, some less than others. Drought tolerant means the plant, once established, can tolerate periods of drought. The first couple of years, especially, all plants need watching and pampering.
My favorites sun and heat loving plants include:
Trees: Bay, olive, pistache (Pistache chinensis), oak, sumac, California bay and strawberry tree.
Shrubs: bottlebrush, ceanothus (not all are drought-tolerant, so check label), rockrose, smoke tree, lavender, rosemary, pomegranate, lavender cotton and germander.
Ground covers: evergreen currant (Ribes viburnifolium), hypericum, thyme, verbena and wisteria.
Perennials: yarrow, agapanthus, agave (most), desert spoon (Daslyrion wheeleri), red yucca (Hesperaloe parviflora), bearded iris, sticky monkey flower and fountain grass.
Cut lavender back severely, almost to the ground, once it has finished blooming. Lavender only lasts about five or six years before it gets woody and needs to be replaced.
Any additions to the garden should be planted in the evening and watered well. If it's really hot and sunny, put a piece of shade cloth or newspaper over the plant until it is acclimated to the site.
Cut flowering stems of yarrow, columbine, salvia, coreopsis and butterfly iris to the ground after they've finished blooming. Keep dahlias deadheaded.
Pinch back fall-blooming chrysanthemums and asters to keep them bushy.
Deeply water grapevines, fruit trees and ornamental trees.
Shop for fall blooming and winter blooming annuals at local nurseries.
Brighten up dark corners with coleus and impatiens. They'll bloom until November.
Shear back petunias and coreopsis; they'll respond with another crop of flowers.
Fertilize almond, nectarine, apricot, peach, cherry and walnut trees this month.
Time to plant broccoli, spinach, cauliflower, cabbage, onion sets, peas, carrots, garlic and beets. Add organic matter to the soil before planting.
Don't ignore potted plants. Water them deeply and thoroughly at least once a day.