Engelmann Oak (Quercus engelmannii) is the rarest species of California's mainland oaks. It is a moderately fast-growing tree with a large mature canopy and interesting form. It is a keystone species, vital to an enormous array of butterflies and birds in Southern California.
Their shape evokes the natural beauty of the land that existed before colonization and suburban sprawl, which have decimated most populations of this attractive tree.
The Engelmann Oak is evergreen and drought tolerant once established. They can be drought-deciduous if they get stressed during hot summers, but their blue-green, leathery leaves will return later in the year.
We love Engelmann Oaks for both their appearance and their innumerate benefits to both people and wildlife. Their robust, wide canopies are vital to providing more shade in our communities and reducing the spiraling effects of heat islands on our local climates.
Their grayish-brown bark is furrowed and thick, coating trunks and branches that twist with age in an attractive and interesting way. Engelmann Oaks have inconspicuous, cylindrical flower clusters in late winter/early spring.
Pollinated flowers develop over 6 to 8 months into mid-sized acorns, which are an important winter food source for local wildlife.
Engelmann Oaks need plenty of care and attention to help them get established. They tolerate dry soil but do best (and stay evergreen) when they are situated near a damp or irrigated area and/or an area where they can reach ample groundwater.
They thrive in full sun but tolerate partial shade, which can be preferable when they are younger and still getting established. They can tolerate a wide range of soil types and drainage speeds.
The native range of Engelmann Oak includes Los Angeles County, Orange County, San Diego County, San Bernardino County, and Riverside County.
Quercus engelmannii - Engelmann Oak (Mesa Oak)
Optimal Growth Conditions
- Mature Height: 33 - 66 feet
- Mature Width: 80 - 90 feet
- Sun: Full Sun, Filtered Sun, Partial Sun
- Water: Low, Moderate
- Soil Drainage: Fast
Geographic Appropriateness
- USDA Zone: Zones 8 - 10
- Sunset Zone: Zones 7 - 9, 14 - 21
- Native Sites: Gentle rocky slopes, grassy mesas with plenty of groundwater, or upslope from riparian woodlands (such as in Englemann Oak Woodland) above plains. They are also found near chaparral or valley grassland. They typically grow below 4200 feet in areas of Southern California that have cooler winters. Suburban sprawl has unfortunately eliminated these oaks from the majority of their native range.
Additional Landscaping Information
- Characteristics: Wide Canopy, California Native, Drought Tolerant, Evergreen, Summer Semi-Deciduous, Deer Resistant, Rare Species, Threatened or Endangered Species, Keystone Species
- Special Uses: Shade Tree, Bank Stabilization, Street Tree (check local guidelines before planting), Butterfly Gardens