Quercus Garryana: Garry Oak
The huge, elegant tree you see standing alone in the field as you drive down the back roads of the Willamette Valley is the Oregon White Oak, Quercus garryana.
Plant care & info
Family: Fagaceae
Genus: Quercus
Common name: Garry oak, Oregon white oak
From British Columbia south through northern California, primarily along the temperate corridor that includes Puget Sound and the Willamette Valley.
A majestic tree with a spreading canopy of dark green, classically-oak-lobed leaves about three inches in diameter. Bark is an attractive fissured gray. Produces an abundance of reddish brown acorns, which are a favorite with many species of birds. Deciduous leaves turn yellow-brown in fall. Grows very large and densely in fertile soils, smaller and more contorted in poorer, rockier conditions. Tends to stay shrubbier in typical garden settings.
Oregon white oak is found growing everywhere from seasonally wet meadows to dry, rocky outcrops; but even the wetter locations still have dry summer conditions. Plant in a sunny location with good drainage, where it won’t get summer water.
This tree can be afflicted with fungal diseases, so be sure to plant it in a location with adequate drainage and lack of summer water—both of which can go a long way in protecting your tree from fungal damage. Gall wasps may also be attracted to it and produce small galls on the undersides of leaves. These, however, don’t appear to cause any damage to the plant. More good news: Q. garryana has not been shown to be affected by the disease causing what is commonly called Sudden Oak Death!
Given full room to spread its lush branches, it becomes the epitome of the “mighty oak” of literature. It can eventually command a space seventy-five feet tall and sixty feet wide, with roots growing far beyond the boundaries of its branches. In most garden sites it holds itself to much less gargantuan stature, and is very slow-growing, reaching only about twenty-five feet in twenty years.
Though you need a bit of space to house an Oregon oak, it is worth the garden real estate. Laden with the recognizably lobed, classic oak leaves of deep dark green, it produces an abundance of small acorns in summer and fall that are a favorite of many species of birds— making it an excellent choice for a wildlife-attracting garden. Their flowers are of little notice, but the fall foliage is yellow to coppery-orange/brown, and provides an attractive contrast to the fissured gray of the trunk. A deciduous tree with intricate branching, it also provides a sculptural element in winter.
If you’d like to introduce an Oregon oak to your landscape, you’ll need a site with full sun and excellent drainage that receives no water throughout the summer. Some fungus issues and lack of vigor can often be traced to retained moisture in the soil.
Numerous insects make use of the native Quercus, most of which do little or no damage to the tree. Occasionally, they may feast on the acorns, which should be of no bother unless you are trying to use them for food or commercially (and may indeed provide food source for visiting birds). The tiny gall wasp (Cynips maculipennis) is responsible for the small galls that sometimes appear on the underside of the tree’s leaves, but they do not seem to negatively impact the health of the tree itself. There are also certain moth larvae for which the oak is the only food source. So the native Quercus is truly a full-spectrum habitat plant!
There are many native shrubs and perennials that grow companionably with Quercus garryana, so you can very successfully use it as the anchor for a more extensive native plant garden, and enjoy it throughout the year and for many, many years.
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We offer a great selection of Northwest Natives from spring through fall. The plants featured are highlighted favorites, but they do not represent ALL of the plants we carry. For a more complete list, see our Northwest Native Plant List.
