Oaks of the Santa Barbara Botanic Garden

Engelmann's Oak

A beautiful Engelmann oak (Quercus engelmanii) can be found at the southeast corner of our Meadow Section. Naturally, this species occurs in the southwest corner of California and into Baja. Decades of urbanization have converted much of the historic Engelmann oak habitat in its range and most trees of this species can be found in San Diego County.

Palmer Scrub Oak

The Palmer scrub oak (Quercus palmeri) is a small, shrubby oak of arid lands. This shrubby tree can be found in California, Arizona, and New Mexico. Their distinct leaves are rounded with fine serrations and often fold in interesting ways. In general, scrub oaks are slow-growing plants, but the Jurupa Palmer oak in Riverside County has been cloning itself from its roots for over 13,000 years, making it one of the earth's oldest living things!

California Black Oak

California black oak (Quercus kelloggii) is a mountain species, found from foothills to mixed forests on mid-elevation slopes. This species has deeply-lobed leaves with bristles at the tips of the lobes. Black oaks are a deciduous species, losing their leaves every fall/winter. They can provide some of the most impressive fall color displays in California.

Canyon Live Oak

Canyon live oak (Quercus chrysolepis) grows from Oregon to Baja California and Arizona. The bulk of this species' range is in the steep canyons of California's mountains. Though small in the Garden, canyon live oak can become massive specimens.

Tanoak

Though technically not a true oak, tanoak (Notholithocarpus densiflorus) is a tree that produces an acorn-like fruit. In Santa Barbara and Ventura Counties, the southernmost members of this species grow in cool north-facing canyons. At the northern end of its range in the coastal ranges and Sierra Nevada, tanoak grows among giant conifers such as pines and redwoods. As with many oaks, tanoak contains abundant tannins in its bark. These chemicals are found in a variety of plants and in low concentrations, produce the bitter flavors in fruits and wine. In higher concentrations, tannins have been used to tan hides. The generally rich tannin content of oaks and their kin is why acorns must always be leached before consumption.

Tucker Oak

Tucker oak (Quercus john-tuckeri) grows on rocky slopes above California's deserts and arid valleys. It bears distinctive silver-green foliage and can develop sculptural, twisting architecture.

Island Scrub Oak

The range of island scrub oak (Quercus pacifica) is limited to three of the Channel Islands, Catalina, Santa Cruz, and Santa Rosa. It was described as its own species in 1994, demonstrating how much we are still learning about California's plants!

Macdonald Oak

Oak biology is interesting for a variety of reasons. One of the most fascinating aspects of oaks is their affinity for making wild hybrids. Macdonald oak (Quercus X macdonaldi) is one such example. This is a wild-occurring hybrid between valley oak (Q. lobata) and island scrub oak (Q. pacifica). As with other hybrids between deciduous and evergreen oak species, the leaves of Macdonald oak are particularly interesting. Their margin (edge) is often halfway between the spiny scrub oak leaf and the lobed valley oak leaf. Sometimes, the leaves of Macdonald oak can be semi-deciduous, persisting on the branches with fall color for several months of the year.

Gander Oak

Gander oak (Quercus X ganderi) is a hybrid between California black oak (Q. kelloggii) and coast live oak (Q. agrifolia). As with other oak hybrids, this variety exhibits very interesting leaves. Our specimen in the Garden was planted in 1942 and serves as one of the most magnificent shade trees in our collection.

Inland Scrub Oak

Inland scrub oak (Quercus berberidifolia) is among the most widespread oaks in California. It grows in chaparral plant communities in the hills and mountains above the coast from Baja to the north end of the Sacramento Valley. Inland scrub oak can also be found in a few foothill locations within the Sierra Nevada Mountains and as far east as San Timoteo Canyon in the northwestern foothills of the San Jacinto Mountains.

Island oak

As the name implies, island oak (Quercus tomentella) grows on California islands, including Santa Rosa, Santa Cruz, Anacapa, Catalina, and San Clemente. It can be found as far south as Guadalupe Island, off the coast of Baja, Mexico.

Huckleberry Oak

Huckleberry oak (Quercus vaccinifolia) is a shrubby oak that can be found on steep slopes in the Sierra Nevada mountains north of Shaver Lake, and into the Coast Ranges of Mendocino County northward. This interesting species has a similar growth form to most scrub oaks, rarely exceeding 2m in height, but it has broad leaves, which are distinct from most scrub oak species.

Valley Oak

Valley oak (Quercus lobata) can grow to be the largest oak in North America. As the name suggests, these trees prefer valley bottom habitat, where there is deep, loamy soil and available ground water. This species' epithet, lobata, refers to the rounded lobes of the leaf margin. Compare this leaf to the leaf of CA Black oak, which has "toothier" margins.