Description

The Engelmann oak is a species made rare by habitat destruction in its southern California native range. The largest stands may be found in San Diego County. A large stand may also be found in the Los Angeles County Arboretum and Botanic Garden. There appears to be a movement of sorts to plant Engelmann oak as a street tree in Santa Clara County. The few I have seen appear to be thriving. In form the Engelmann oak reminds one of a valley oak, Quercus lobata, with its rounded or elliptical form, open structure and twisted branch structure. Then the leaves and furrowed gray bark seem more similar to the blue oak, Quercus douglasii. Scientists, however, have confirmed that the Engelmann oak is more closely related to sub-tropical oaks of the Southwest and northern Mexico. Engelmann oak is adaptable but appreciates access to nearby water. Plant near (not in) a regularly watered feature or provide occasional deep summer watering at the drip line. In Santa Clara County and elsewhere, planting in the lower foothills (Sunset zone 16) may help reduce the risk of damage during a hard frost, though the Engelmann oak is considered cold hardy into the low 20’sF.