Oaks in California

Several species of oak are native to California. I have been trying to learn more about them, and learn how to identify them. Identification is still tricky; some species are distinctive, others seem very similar to each other. Here are a few native oaks that I’m learning to recognize:

• Quercus agrifolia – also called Coastal Live Oak, California Live Oak, and California Field Oak. This evergreen tree thrives in coastal conditions, within 50 miles of the ocean, and in a forest setting. Leaves are slightly elliptical, 1-2 inches long, glossy dark green on the upper side, and serrated. Bark is smooth and dark gray. Male flowers are catkins; female flowers are flowered spikes. The cap of the acorn encloses 1/4 to 1/3 of the nut. Trees can reach 70 feet in height.
• Q. chrysolepsis – also called Canyon Live Oak, and Canyon Oak. This evergreen tree is native to foothills, mountain slopes, and canyons. Its range is the entire length of California, from sea level to 9,000 feet. Yosemite has groves of Canyon Oak. Leaves are elliptical, 1-4 inches long, glossy green on the upper side and grayish and felt-like underneath, serrated when young, then smooth when old. Bark is pale gray and furrowed. Flowers are similar to Q. agrifolia. The cap of the acorn encloses 1/4 of the nut, and the acorn is small and egg-shaped. Trees can reach 60 feet in height.
  
• Q. garryana – also called Garry Oak and Oregon Oak. This deciduous tree thrives from British Columbia to the Santa Cruz Mountains in California. Leaves are lobed, 3-6 inches long, dark green glossy above (turning reddish brown in fall), and downy underneath. Bark is gray, scaly, and checkered. Flowers are similar to Q. agrifolia. The cap of the acorn encloses 1/3 of the nut. Trees can reach 90 feet in height.
  
• Q. kelloggii – also called California Black Oak and Kellogg Oak. This deciduous tree thrives in the foothills of the Sierra Nevada and in the Coast Ranges, but away from the coast. Leaves are oblong, to 6 inches long, divided into dentate lobes, glossy green above (turning to yellow or yellow orange in the fall), and pubescent underneath. Bark is dark, furrowed, and checkered. Flowers are catkins. The cap of the acorn encloses 1/3 to 1/2 of the nut or more. Native people groups used the acorn as a staple food. Trees can reach 80 feet or more in height.
  
• Q. lobata – also called Valley Oak, California White Oak, and White Oak. This deciduous tree is native to California’s Central Valley and foothills away from coastal influences. It prefers rich, well-watered bottom land. Leaves are deeply lobed, 3-4 inches long, dark green above and paler gray-green and felt-like underneath. Flowers are catkins. The cap of the acorn encloses 1/4 of the nut, and the acorn is elongated. Native people groups used the acorn as a staple food. Trees can reach 80 feet in height.

Q. lobata at The Ruth Bancroft Garden is 350 years old.

Q. lobata leaves are lobed. Leaf shape, bark, flowers, and fruits are used collectively to identify a tree.

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These descriptions have been compiled from: Hortus Third (Bailey), Plant Life in the World’s Mediterranean Climates (Dallman), and The Western Garden Book (Sunset).