The stout, sprawling branches of a mature white oak are a cradle for a staggering variety of wildlife and an iconic site in open, wild spaces. Before white settlement, Oregon white oak woodlands and savannas were a common habitat type throughout the Willamette Valley. Sadly, scientists estimate that only about seven percent of the oak woodland and two percent of the oak savanna habitat remains in the valley today.
- Plant type/canopy layer: deciduous large tree
- Size at maturity: 40-90' tall, 30-70' wide
- Light requirements: full sun
- Moisture requirements: dry to moist soil, well-drained
- Bloom time: April - June
- Growth rate/ease: appears slow growing, but actually moderate growth rate over the long-term (see note below), moderately easy to grow
- Wildlife support: deeply fissured bark and hollow branches of old trees provide nesting sites for birds, squirrels, bats and other small animals; flowers are a nectar source for adult butterflies, bees and other insect pollinators; leaves are a larval food source for moths and butterflies; acorns that provide food for many small animals, deer and woodpeckers; overall plant attracts and supports beneficial and other pest eating insects and is a caterpillar host
- Native habitat/range: common in open grasslands, dry hillsides, and woodlands of the PNW, west of the Cascades, particularly dense throughout the Willamette Valley. Portland Plant List - yes.
- Special features & uses: wildlife favorite; medicinal; acorns are edible; landscape uses include erosion control, hedgerows and windbreaks
Gardening with Oregon White Oak: If your neighborhood's natural areas feature Oregon white oaks, and you have the space, consider planting this meaningful investment in our region’s future! They will thrive with ample sunlight found in savanna and open woodlands with dry to moist soil. Be prepared to water deeply, but infrequently in the first 2 - 3 years as it becomes established. Many people think this tree is slow growing because, in the early years it focuses its energy on a massive amount of root growth, setting the foundation to provide 500 years of essential ecosystem services like critical wildlife habitat and carbon sequestration. This below-the-surface growth goes unnoticed but after 5-10 years, the above-ground growth kicks in, and follows a moderate pace.
Photo Credit 1: "Quercus garryana var. garryana" by Thayne Tuason is licensed under CC BY-NC 2.0
Photo Credit 2: "Spherical acorns of Oregon oak, (Quercus garryana)" by edward_rooks is licensed under CC BY 2.0
Photo Credit 3: "Camassia and Quercus Garryana (Garry oaks)" by ngawangchodron is licensed under CC BY-NC 2.0
Photo Credit 4 & 5: "Quercus garryana -- (Oregon white oak)" by steven.k.sullivan is licensed under CC BY-NC-SA 2.0