Canyon Oak Quercus chrysolepis

Canyon live oak is a broadleaf evergreen medium-sized tree that may grow to a height of 80 feet and up to 2 feet in diameter. On mountain slopes and ridge tops, it is known to grow as a dense shrub up to 15 feet tall.  The tree has a broad trunk, and the crown may be rounded to spreading. The leaves are evergreen, thick, leathery, and shiny dark green. The margins are usually entire on mature leaves, but young leaves have spiny margins like a holly leaf. Flowering in the spring, the male flowers are wooly catkins, and the female blooms are short spikes. The fruit is an acorn with a distinctive golden wooly cap; hence, its common name, Golden-Cup Oak. This tree grows very slowly, but it can live up to 300 years. It is a member of the Fagaceae or beech family. 

The canyon live oak is native to western Oregon, California, western Nevada, Arizona, New Mexico, and northeast and northwest Mexico. It is typically found in canyons, moist slopes, or along stream banks. It is considered to be the most beautiful and most widespread oak in California. Growing on steep and rocky slopes helps to stabilize the soils.

The origin of the genus name, Quercus, is Latin and means "oak tree. The origin of the species name, chrysolepis, is the combination of two words. Chryso means "gold," and lepis means "scale". Golden scale refers to the tree's yellowish or golden acorn cap. Many of the common names of this tree reference its distinctive fruit. Maul Oak references its hardwood for use in making mauls for splitting wood.

Canyon Live Oak prefers full sun, well-drained soils, and can tolerate drought once established. It grows best in acidic to neutral pH soils. It is tolerant of most other soil types and exhibits tolerance to salt spray. Oak trees are difficult to transplant due to their sensitive root systems. The tree is best propagated by seeds.

This tree provides a habitat and food source for a variety of wildlife. The acorns are a food source for Steller jays, woodpeckers, wild turkeys, squirrels, bears, and mule deer. Deer may use the foliage for food. Canyon live oak also serves as a host plant for butterflies including the Western Tiger Swallowtail. 

Canyon Live Oak makes an attractive landscape tree. The tree can grow on steep slopes and would help prevent soil erosion.

Seasons of Interest:

Bloom:  Spring          Foliage:  Spring, Summer, Fall, and Winter        Fruit:  Fall 

Quick ID Hints:

• medium-size tree, dense, erect, and widespread branching
• unlobed, thick, leathery, glossy dark green leaves on the upper surface, and bluish-white with some stellate and glandular hairs on the undersides
• young leaves are golden and wooly or felt-like on the undersides. 
• leaf margins vary from entire on mature leaves and spiny on young leaves
• male flowers catkins and female flower short spikes 
• chestnut brown acorns with distinctive fuzzy, wooly golden caps 

Insects, Diseases, and Other Plant Problems: The canyon live oak is susceptible to borers, aphids, orangestriped oakworm, buck moth, whitemarked tussock moth, and caterpillars. It may also develop sudden oak death and crown rot.  The parasitic plant, Mistletoe, and honey fungus or armillaria are known to occur. Acorns can be destroyed by weevils and worms. Deer may browse seedlings and saplings.

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common pests and insects. 

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University