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Quercus garryana
Oregon white oak, Garry oak
Western North America (British Columbia to northern California)Learn more
Growing Zones
USDA Hardiness Zones
6 - 8These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →Frost Tolerancehardy
Overview
Quercus garryana is a medium to large deciduous tree reaching 40-80 feet (12-24 m) tall with a spread of 40-60 feet (12-18 m), developing a broad, rounded crown with massive, often gnarled spreading limbs on open-grown specimens. This is the only native oak in the Pacific Northwest and British Columbia, and defines the oak savanna and prairie ecosystems of the region. Bark is light gray, shallowly fissured with scaly, blocky ridges. Leaves are alternate, simple, obovate, 3-6 inches (8-15 cm) long, with 5-7 deep, rounded lobes (no bristle tips — a white oak group characteristic). Foliage is dark green and leathery above, paler and slightly pubescent beneath. Fall color is yellow-brown to russet, variable and not a strong ornamental feature. Flowers are monoecious catkins in April to May, inconspicuous. Acorns are ovoid, 1-1.25 inches (2.5-3 cm) long, with a shallow, warty cup enclosing about one-quarter of the nut, maturing in one year. Growth rate is slow at 6-12 inches (15-30 cm) per year, particularly in youth. Trees are extremely long-lived, commonly reaching 250-500+ years. Develops a deep taproot, making transplanting of specimens larger than 2-3 inch caliper very difficult. Open-grown trees develop massive, gnarled, spreading limbs that are the species signature; forest-grown trees are taller with a narrower crown. Oregon white oak ecosystems are among the most threatened habitat types in the Pacific Northwest, having declined by over 90% since European settlement due to fire suppression, development, and conifer encroachment.
Native Range
Native to western North America from southern British Columbia south through Washington, Oregon, and into northern California. Occurs in oak savannas, prairies, woodland margins, and dry rocky slopes from sea level to 4,000 feet (1,200 m). The only native oak in British Columbia and the dominant native oak in western Oregon and Washington. Named for Nicholas Garry of the Hudson Bay Company.Suggested Uses
Planted as a specimen or shade tree in large landscapes, parks, and restoration plantings. Space 30-40 feet (9-12 m) from structures. Do not irrigate during summer once established. Conservation and restoration of oak savanna and prairie ecosystems is a regional priority. Acorns provide food for wildlife including jays, squirrels, woodpeckers, and deer. Long lifespan of 250-500+ years makes this a multi-generational legacy tree. A Great Plant Picks recommendation.How to Identify
Appearance
Size & Dimensions
Height40' - 80'
Width/Spread40' - 60'
Reaches mature size in approximately 40 years
Bloom Information
Monoecious catkins appear in April to May concurrent with leaf emergence. Male catkins are pendulous, yellowish-green. Female flowers are inconspicuous. Bloom is not ornamentally significant. Acorns mature in one year, ripening in September to October.Detailed Descriptions
Flower Description
Yellowish-green (catkins, inconspicuous)Foliage Description
Dark green, leatheryGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Water deeply once per month during the first two summers after planting. Once established, do not irrigate during summer — summer water promotes root rot (Armillaria mellea and Phytophthora species) in this drought-adapted species. Plant in full sun; intolerant of shade. Requires well-drained soil. Transplant only small, container-grown or young balled-and-burlapped stock; the taproot makes transplanting of larger trees extremely difficult. Protect existing mature trees during construction — do not alter grade, compact soil, or irrigate within the dripline. Sudden Oak Death (Phytophthora ramorum) is a concern in Oregon; follow quarantine guidelines. Oak gall wasps produce disfiguring but generally harmless galls on twigs and leaves.Pruning
Prune in late winter (January through February) while dormant. Mature trees require minimal pruning. Remove dead, damaged, and crossing branches. Avoid heavy pruning of established trees; wound closure is very slow. On young trees, establish a central leader and remove codominant stems. For existing trees affected by conifer encroachment, selective conifer removal rather than oak pruning is the appropriate management response.Pruning Schedule
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