Shrubs, evergreen, 0.2–0.3(–0.5) m, matlike. Stems spreading, sometimes rooting at nodes; branchlets green, sometimes tinged red, not thorn-tipped, usually round, sometimes angled, in cross section, flexible, puberulent. Leaves: petiole 3–11 mm; blade flat, elliptic to widely ovate, 12–45 × 6–20 mm, base obtuse to rounded, margins serrulate to denticulate, not revolute, usually not wavy, sometimes wavy, teeth 27–42, apex ± obtuse to rounded, abaxial surface pale green, pilosulous, adaxial surface green, pilosulous; usually pinnately veined, rarely 3-veined from base. Inflorescences axillary, umbel-like to racemelike, 1.3–4 cm. Flowers: sepals, petals, and nectary usually blue to pale blue, rarely white. Capsules 4–5 mm wide, weakly lobed near apex; valves smooth, crested.
Phenology: Flowering Apr–Jun.
Habitat: Well-drained slopes and canyons, open to shaded sites, mixed evergreen and conifer forests.
Elevation: 700–2300 m.
Ceanothus diversifolius occurs in the North Coast Ranges and the western slopes of the Cascade Range and the Sierra Nevada; it often forms mats to two meters wide. Marginal teeth on young leaves are notable in having more or less persistent, narrowly conic glands, not seen elsewhere in Ceanothus.