Ceanothus impressus is a species of flowering shrub in the Rhamnaceae (Buckthorn) family known by the common name Santa Barbara Ceanothus. This species is endemic to a small area of the Central Coast of California, where it can be found on coastal slopes and mesas. It is thickly branched with dark brown twigs and stem. The very small, evergreen leaves are about 2 centimeters long and oval shaped, highly ridged and wrinkled and curling under along the edges. They may be gland-dotted and have grayish hairy undersides. The shrub flowers abundantly in flower clusters of small blue flowers. The fruit is a crested spherical capsule about 4 millimeters wide.
There are two recognized varieties that inhabit essentially the same small range. In addition, several popular cultivars are derived from this species including ‘Dark Star’ and ‘Julia Phelps.’ This is a great Ceanothus to grow in its natural range. Significant amounts of summer water will kill this plant. It needs the cool coastal climate and strong marine influence to make it through the hot season, so don’t try to grow it south of Ventura County or inland areas. Prefers sun or part shade and sandy soils. Makes a great hedge.