The Most Majestic Southern California Oak

A remnant Engelmann oak grove, one of the highlights of the Los Angeles County Arboretum & Botanic Garden, covers much of a knoll in the southwestern corner of the arboretum. Plant enthusiasts planning a visit for the first time should make an effort to include this naturally occurring population on their tour, especially during winter and spring.

Quercus engelmannii is native to southern California and is commonly known as Engelmann oak, Pasadena oak, or mesa oak. It occurs in the South Coast, south Channel Islands, San Gabriel Mountains, Peninsular Ranges, and San Jacinto Mountains floristic regions, and in Baja California Norte.

This species is somewhat of an outlier in California: its closest affinities are with Arizona white oak (Quercus arizonica) and the subtropical blue oak of Mexico (Q. oblongifolia), making it the northernmost subtropical oak species.

California botanists once considered Quercus engelmannii to be closely related to Q. douglasii because of similarities in habitat occurrence and leaf color, but such is not the case. Considerable variation in leaf form within a tree and among trees is common in California oaks but seems to be more prevalent ...