Please remember that many natives should only be planted in the fall and winter. Planting natives that are prone to root rot during the late spring to early fall could prove deadly to these plants if excellent drainage is not provided. Such plants are ceanothus, manazanita, fremontodendrom, and some salvias ( black and white sages).
Root rot can occur if the soil is not allowed to dry in between waterings. The combination of moisture and high temperature is a perfect medium for mold and fungus growth.
If you have more clay like soil with poor drainage consider making an elevated bed for your more sensitive natives. Keeping the the main root ball above the surface of your hard soil will allow the roots a better chance to drain.