@tpolytmus 1/
There are many plants that can help make hillsides resistant to mud slides in Southern California. According to a website called Green Thumb1, some of the best shrubs for this purpose are:
Dwarf Coyote Brush
California Buckwheat
Coastal Sagebrush
California Bush Sunflower
@tpolytmus 2/
Apache Plume
Coast Goldenbush
Matilija Poppy
Sages
Wooly Blue Curls
These shrubs can help prevent soil erosion and hillside stabilization by retaining water and anchoring the soil with their roots1.