Oregon White Oak (Garry Oak)
Quercus garryana · Deciduous, Broadleaf, Hardwood
Plant Family
Fagaceae
Tree Category
Shade Tree, Forest Tree, Nut Tree
Variety / Cultivar
Native species (Wild type)
Hardiness Zones
USDA Hardiness Zones 6 through 9; highly adapted to mediterranean-style climates with wet winters and dry summers.
About This Tree
A massive, long-lived tree with a broad, rounded, spreading crown. Often develops crooked, gnarly branches that give it a rugged, structural appearance. Growth rate is slow to moderate.
Leaf Characteristics
Simple, alternate arrangement; 3-6 inches long with 5-7 deep, rounded lobes (sinuses); leathery texture; dark shiny green on top, paler and slightly fuzzy underneath; turns yellow-brown in fall.
Bark Characteristics
Grayish-white to light gray; thick and corky with deep furrowed ridges and scaly plates; provides excellent fire resistance.
Growing Information
Origin Region
Native to Western North America, primarily the Pacific Northwest from British Columbia to California.
Growing Season
Leafs out in late April/May; flowers (catkins) appear with leaves; acorns ripen in autumn; enters dormancy after shedding leaves in late October/November.
Sunlight & Water Needs
Full sun is required for best form; very drought-tolerant once established; prefers well-drained soil; sensitive to overwatering or soil compaction near the root zone.
Mature Size
Height of 50-90 feet with a similar or wider spread of 40-80 feet; can live for over 300-500 years; trunk diameter can reach 3-4 feet.
Special Characteristics
Highly drought-tolerant and fire-resistant. Historically used by Indigenous peoples for acorns (food) and wood. High timber value for flooring and barrels, though primarily conserved today for habitat.
Wildlife & Ecology
Keystone species; produces acorns that feed squirrels, jays, and deer. Provides nesting cavities for woodpeckers and owls. Supports hundreds of insect species and is a critical component of the endangered Oak Savannah ecosystem.