Ceanothus integerrimus, known by the common name deer brush, is a species of woody shrub in the family Rhamnaceae, native to the western United States in Arizona, New Mexico, California, Oregon, and Washington.

[2][3] Ceanothus integerrimus is a deciduous shrub from 1–4 metres (3.3–13.1 ft) tall with an open ascending to erect branch habit.

The leaf blade is lanceolate, elliptical or oblong to widely ovate in shape.

[3] It regenerates by seed, shoot formation from the crown and stem, and also by layering when branches come in contact with soil.

[5][7] Seeds germinate best at about 1 inch soil depth in shady areas in the spring following fire scarification.

C. integerrimus is an important part of forest regeneration after wildfires by providing nitrogen.

[14] The Miwok Indians of Northern California also use the branches of this plant in weaving complex baskets.