Big Pod Ceanothus - Ceanothus megacarpus covers many a slope in the Santa Monica Mountains. Towards the end of January, the plant begins to bloom. In years with above average rain, our slopes may appear to be covered in snow from the multitude of tiny flowers produced by this shrub. One reason is that Ceanothus shrubs of the same species in an area often bloom at the same time. Ceanothus megacarpus is endemic to southern California’s Transverse Ranges and the Channel Islands.

Ceanothus megacarpus is an evergreen shrub that can reach 4 meters (13 feet) in height. For a shrub with shallow roots, it has a high tolerance for drought. Seed production begins 5 years after germination. The fruit of this shrub is a capsule containing seeds. Seed dispersal is accomplished by ejecting the seeds with force, however, most seeds drop to the ground. The seeds are a food source for small mammals and insects. Seed production suffices to collect in the leaf litter and soil, forming a persistent seed bank. This is important, the plant does not re-sprout from its stump after a fire.

When identifying this plant, look for the stipules - wart-like appendages at the base of branch nodes. A single leaf appears on each node along the stem - other local Ceanothus species have pairs of leaves positioned on their stems. Flowers look like other Ceanothus species - it can be very difficult to identify a species on the flowers alone. Looking at the specific traits of the leaves and stalks makes this task easier to do

In the Santa Monica Mountains, this shrub is challenging Chamise as the dominant shrub. Source: Ceanothus megacarpus - Adenostoma fasciculatum Shrubland

Ceanothus: from the Greek keanothus, a name meaning thistle or spiny plant which was applied by Theophrastus and/or Dioscorides to an Old World plant believed by some to have been Cirsium arvense, and reused by Carl Linnaeus when he published it in 1753.
megacarpus: large fruited www.calflora.net is the source of this info.