In southern california, most landscapes start with the lawn, but the best advice is to mix the terrain with a mix of naturally occurring wild vegetation from the native environment. Just like native grasses, native plants meant to grow in the southern California climate will grow better root networks that will help with water absorption. For grass suggestions for SoCal, drought tolerant grasses are also often preferred because they can tolerate various soil conditions, have many fibrous roots that grow quickly.
Grass suggestions: Zorro Annual Fescue, Vulpia Myuros Blando Brome, Bromus Mollis Cucamonga Brome, and Bromus Carinatus.
Often these grasses are chosen for revegetation of slopes that have in past experienced fires. If working to stabilize a property for flood or past fires, consider mixing the landscaping with various plant types, a mix of plant heights, and root depths.
Tree and Shrub Flood Prevention suggestions:
Drought Resistant Trees with SoCal roots: Coast Live Oaks, Quercus Agrifolia Redbuds, Cercis sp., Catalina Cherry, and Prunis Lyonii.
Shrubs and Ground Covering plants that impact Flood Prevention: Prostrate Myoporum, Myoporum Parviflorium Capeweed, Arctotheca Calendula, Cultivar “Twin Peaks” Baccharis Pilularis, Descanso Rock Rose, Cistus Crispus Periwinkle, Vinca sp., Trailing African Daisy, and Osteospermum Fruticosum.
Working with a landscaping professional is recommended to plan your drainage methods that will work with your terrain and the various plant needs of your property.