Coast Live Oak
Quercus agrifolia
An iconic California evergreen oak with broad, often ground-sweeping crowns and holly-like leaves. Adapted to dry summers, it resents irrigation and grade changes over its roots; sudden oak death and summer-pruning discipline are key regional concerns.
Field reference
Family
Fagaceae
Growth rate
Moderate
Mature size
30–70 ft tall, 40–80 ft spread
Hardiness zone
9–10
Soil preference
Well-drained California soils; needs dry, undisturbed summer root zones
Sun
Full sun
Pruning window
Mid-summer (dry season) to limit oak-borer and disease spread
Wood properties
Dense, heavy, strong evergreen oak (~0.70+ SG green) with massive, far-reaching limbs. Wide low scaffolds carry huge cantilever loads — rig long laterals with generous safety margins.
Native range
California Coast Ranges and foothills, from Mendocino County into Baja California
Green weight
70 lb/ft³
Pests & diseases to watch
Common questions
Why is summer irrigation bad for coast live oak?
Established coast live oaks are adapted to dry summers, and frequent summer water around the trunk encourages root and crown-rot fungi like Phytophthora. Keep lawns, irrigation, and soil fill away from the root zone of mature trees.
When should coast live oaks be pruned?
Prune in the dry summer months, not winter, to reduce the spread of oak diseases and to avoid the wet-season conditions that favor pathogens. Keep cuts modest on these slow-healing evergreens.
Related species in Fagaceae
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