Buckbrush (Ceanothus cuneatus var. ramulosus) otherwise known as California lilac is an evergreen shrub or tree with simple leaves and small pale blue to lavender or white flowers in profuse clusters on the ends of branches.  It is a plant in the Rhamnaceae  or Buckthorn family.  Ceanothus is one of the most common and widespread native plants in California. It may vary in appearance due to its wide distribution and because its varieties and species hybridize easily.  It will grow in sandy or serpentine soils and is often found in chaparral habitat. 

Ceanothus is tough and fast-growing but may be short-lived. 

It supports insects, especially bees. Butterflies are attracted to the flowers and are known to host 9 species of butterfly and moth with a huge total of 86 species likely.