Timing is important. Summer is a great time to remove a lawn but hold off on planting your new drought tolerant plants until late fall, taking advantage of cooler temperatures and winter rain.
Sometimes removing a lawn can reveal unpleasant surprises, which in the past just got mowed over. Oxalis pes-caprae was brought over from South Africa years ago as an ornamental. In cool weather, its yellow flowers and clover-like leaves are very attractive, but it soon takes over entire yards and looks awful when it dies. Bulbs must be removed completely to get rid of it. Nut sedge looks like grass and blends in perfectly with a mown lawn. Once the lawn grass is gone, it will keep popping up until you remove all the tubers (“nutlets”) at the end of its roots. If your previous lawn had Bermuda grass in it, keep in mind that it has underground stems growing deep into the ground that must be completely removed or it comes back and crowds out your new plantings. And even those weeds that can easily be hand pulled can come back by the thousands in a yard with a large weed “seed bank.”
A much pleasanter summer activity is visiting our own Fullerton Arboretum to get ideas for your fall planting. I love the “buckwheats” (genus Eriogonum), which range in size from low growing perennials to large shrubs like Saint Catherine’s Lace (Eriogonum giganteum) now in full bloom in the Arboretum’s Channel Islands garden. It has masses of tiny lacy white flowers that provide nectar and pollen for bees, butterflies, and flower flies. In late summer and fall the flowers turn an attractive brown attracting seed-eating birds.
When at last fall arrives with its great fall plant sales, it may be tempting to buy your plants in the largest pots available in hopes of creating an instantly mature garden. Actually, smaller plants adapt more quickly to your soil and soon catch up. Your new purchases will require water to get established. I like hand watering, or you could use drip irrigation. Using sprinklers to water the entire yard including places where nothing is planted will waste water and encourage weeds. Sow California wildflower seeds in the unirrigated spaces. My wildflowers rely on rainfall alone. The seeds germinate when the late fall/winter rains begin and the flowers bloom profusely in spring. Then they die after leaving plenty of seed to begin the cycle again the next year (with seeds left over for seed-eating birds).