E-Flora BC: Electronic Atlas of the Flora of British Columbia

Quercus garryana Douglas ex Hook.
Garry oak (Oregon white oak)
Fagaceae (Beech family)

Introduction to Vascular Plants

© Gary Ansell  Email the photographer   (Photo ID #13500)

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Distribution of Quercus garryana
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Quercus garryana var. garryana

Species Information

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Deciduous tree with heavy, craggy branches, up to 25 m tall but often small, shrubby and as short as 1 m in dry, rocky habitats; trunks up to 1 m wide; bark light grey with thick scaly ridges.
Alternate, deciduous, blades oblong to egg-shaped in outline with 3-7 lobes per side, the lobes entire or 2-3 toothed, up to 12 cm long with stalks 1-2 cm long, the largest sinuses extending more than halfway to the midrib, bright shiny green and glabrous above, paler below with reddish to yellow hairs, turning yellowish-brown in the fall.
Inflorescence of tiny inconspicuous male and female flowers, these separate but on the same tree; female flowers clustered or single surrounded by a scaly cuplike involucre; male flowers numerous in catkins.
Acorns, 1-seeded, maturing in one season, unstalked, egg-shaped to nearly round, 2-3 cm long; cups shallow, bumpy, hairy within.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Mid Spring
Fruit/Seed characteristics:
Colour: Brown
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Mesic to dry grasslands and rock outcrops in the lowland zone; locally common on SE Vancouver Island and the Gulf Islands, rare in the lower Fraser Valley; S to CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Quercus garryana

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 20 116 315
Slope Gradient (%) 0 34 135
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
23 245 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 2 7
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CDF(81), CWH(1)

Ecological Indicator Information

A shade-intolerant, submontane to montane, Western North American deciduous broadĀ­leaved tree distributed more in the Pacific than the Cordilleran region. Occurs in maritime to submaritime summer-dry cool mesothermal climates on very dry to moderately dry soils; its occurrence decreases with increasing latitude, elevation, precipitation, and continentality. Sporadic to scattered on southeastem Vancouver Island and islands of Georgia Strait (less frequent on adjacent mainland). Usually forms open-canopy stands on water-shedding (rock outcrops) sites. Its calcium-rich bark supports corticolous moss communities. Characteristic of dry mesothermal forests.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is cool mesothermal.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References