Ceanothus is a genus of about 50–60 species of shrubs or small trees in the family Rhamnaceae. The Californian species are commonly known collectively as California lilacs, with individual species having more descriptive common names. Other common names for members of this genus are wild lilac, and soap bush.
Ceanothus flowers are tiny and are produced in large, dense clusters. The seeds of this plant can lie dormant for hundreds of years, and Ceanothus species are typically dependent on wild fires to trigger germination of their seeds. Ceanothus is a good source of nutrition for deer, specifically mule deer on the West Coast of the United States.