San Gabriel Mountains Leather Oak, or Scrub Oak, is a thick, robust, shrub of the chaparral, between 3 and 10 feet tall, that can form impenetrable thickets. Its very firm leaves have variable shapes, but all are densely hairy on the undersides. Its acorn nuts sit in thick, warty cups that seem too short to hold the stout nuts securely. This shrubby oak is (not found anywhere else) to the San Gabriel Mountains.

The leaves are small – up to 2 inches long and about half that wide. The leaf is often slightly convex or flat with inrolled edges, and young leaves are sometimes wavy. The leaf are shallowly or spiny-. Mature leaves are hard, leathery, and more-or-less shiny, with fine hairs on the dark green upper sides and thick, matted hairs on the dull green undersides.

The variable leaf shapes can be confusing when identifying oaks. The dense hairiness on the leaf underside and on the twigs provides a good field mark and aids in the identification of this species. Oaks have separate and on the same tree. Male flowers are borne on slender . The inconspicuous, solitary female flowers appear on short stalks in the leaf . Flowering of Leather Oak is in April and May. The fruit is an acorn that consists of a stout nut held in the acorn cup. The nut is approximately 1 inch long and 1/2 inch wide. The cup seems rather shallow in comparison with the nut size; it is usually 3 times as wide as it is deep. The warty scales on the outside of the acorn cup help distinguish the species from other oak groups.


Oak Gall: The round, spotted red mass that resembles a berry is not a fruit, but an insect . A tiny Beaked Spindle Gall Wasp (Heteroecus pacificus) lays its eggs in the bud of a twig. Secretions from the wasp larvae cause the twig to expand and grow into a mass that protects the developing larvae. In this case, the round gall is red with yellow bumps and a beak-like projection. These galls generally do not harm the tree. When the wasp reaches adulthood, it eats its way out of the gall and flies away. San Gabriel Mountains Leather Oak grows between 1,500 and 4,500 feet in elevation on chaparral slopes and ridges, and in oak woodlands in granitic soil. The variety of Leather Oak that grows in the San Gabriel Mountains is Quercus durata var. gabrielensis, and it grows only here. A second variety, Q. durata var. durata, grows in the and , as well as the northern foothills. Leather Oak belongs to the group. The other member of this group in the San Gabriel foothills and canyons is Engelmann Oak (Q. engelmannii). Oaks within the same group are very closely related and freely. You may encounter examples of such hybridization in the foothills. Coast Live Oak (Q. agrifolia) and Interior Live Oak (Q. wislizeni) are in the Black Oak group, while Canyon Live Oak (Q. chrysolepis) is in the Golden Oak group. All are shown in this interpretive guide.

California Black Oak (Q. kelloggii) grows at higher elevations in the San Gabriel Mountains, as does Chinquapin (Chrysolepis sempervirens), another member of the Oak family. On the desert side, Tucker’s Oak (Q. john-tuckeri) can be found, while the range of Valley Oak (Q. lobata) extends only to the western edges of the San Gabriels. This sturdy evergreen shrub is slow-growing, but long-lived and ideal for providing natural habitat. It offers an attractive natural shape and also can be pruned to fit your garden needs.
Sunlight needs Full sun.
Water needs Only occasional summer water, if any.
Soil needs Adaptable soil.
Acorns are eaten by Mountain Quail, California Quail, California Towhee, Band-tailed Pigeon, Oak Titmouse, Scrub-Jay, Steller's Jay, Spotted Towhee, Acorn Woodpecker, White-breasted Nuthatch, and California Thrasher. In addition, the catkins are eaten by Oak Titmouse and Acorn Woodpecker. Leather Oak is a for California Hairstreak and California Sister. After fires, Leather Oak can from its unburned root . New plants may be able to grow from acorns that were buried in the soil by animals, such as Scrub-Jays, but acorns are sensitive to heat and most do not after a fire. The scrub oaks of Southern California have suffered from much confusion over the years. Prior to about 1982, they were all called Quercus dumosa. Then, except for some small areas close to the coast, they were called Q. berberidifolia, a much harder name to learn. In the early 1990s, further study identified those in the San Gabriel Mountains as a variety of Leather Oak (Q. durata var. gabrielensis). Many older books and plant lists still show them as Q. berberidifolia. If a scrub oak is in the San Gabriels, you should consider it to be a Leather Oak, instead.


Meaning of the Name: Quercus is the Latin name for oak; durata is from Latin and means “hard”, probably referring to the leathery leaves. The variety name, gabrielensis, indicates that it is found in the San Gabriel Mountains.

Leather Oak also refers to the quality of the leaves.