Common Name: 
California Lilac
Wild Lilac

Some 55 species of evergreen and deciduous shrubs, prostrate to erect, and small trees.  Sometimes reported as not long lived, say 5-15 years, other say this is the result of home owners over watering and fertilizing.  Flowers are small, in clusters, showy en masse, color ranges from white through many shades of blue to deep violate.  Fruit a capsule, somewhat thick-walled, more or less globose, but 3-lobed, each lobe 1-seeded.  Their native range extends from southern Canada to Mexico and south to Guatemala, but mainly in California (home to over 40 species).  Some are also found in the eastern US and Rocky Mountains.  Most, if not all, ceanothus have the ability to fix large amounts of nitrogen via symbiotic association with root-inhabiting microbes (actinomycetes).     See the Sunset Western Garden Book for brief descriptions on some 30 Ceanothus species and selections.
Ceanothus: Greek name but its meaning is uncertain.