Planting Oregon White Oak Trees

Oak habitat is in decline

Oregon white oak trees (Quercus garryana) provide a key habitat in Washington County. Oak trees are known as a tolerant species that can survive droughts and resist fire and they support dozens of rare birds and wildlife species. Tualatin Soil and Water Conservation District (Tualatin SWCD) is working to protect this unique and threatened Pacific Northwest habitat.

You can help by planting an oak tree

Majestic, unique, strong, resilient. There are so many reasons we love oak trees. Each oak tree provides habitat, food, shelter and shade for wildlife and people. And we see fewer and fewer each year. In Washington County there are plenty of open areas that would benefit from an oak tree.

Oregon white oak grow slowly. Give them extra care when you first plant them and you’ll be rewarded with a large, graceful tree that makes a big difference for wildlife across our watershed for years to come. As is the saying, the best time to plant a tree is 20 years ago, the second best time is now!

Where to buy

You can find Oregon white oak trees (Quercus garryana) at many local nurseries in Washington County. Oregon white oak are fairly distinct from other oak trees with their rounded leaf lobes. We recommend going to a native plant nursery to find them. Another oak called English oak (Quercus robur) has similar rounded leaf lobes and could be mistaken for Oregon white oak.

Visit our friends at Backyard Habitat Certification Program for a great interactive website that can point you to available plant nurseries in the area.

You can also grow your own oak tree from acorns! We will share more about how to do that below.

Choose your location thoughtfully

When planting, think about 100 years from now. How will a tree that can be 100 feet tall and just as wide fit into the space?

• Pick a sunny location, oaks do best with full sun exposure
• Give the tree at least 40-50 ft of space away from other trees and buildings
• In the Willamette Valley most oak are found in lower elevations, below 2000 ft is a safe bet
• If you plant a bigger tree (more than a few feet tall) you will need to water the tree the first summer or two to help it establish
• Plant in an open area away from prolific weeds (avoid areas with Himalayan blackberry and Reed canary grass)
• Don’t plant directly in standing water; oak can tolerate wet soils but we don’t recommend planting directly into a wetland

Planting and caring for your tree seedling

So the rainy season is upon us and you’re ready to put a new oak tree in the ground? You picked a spacious spot for your new tree and you have your materials ready to go. Here’s what to do next!

Essential supplies for seedling planting: oak seedling(s) & shovel.

Additional supplies: mulch & seedling protector tube(s).

Pro tips for a happy oak tree

Plant your tree in the fall and winter when soils are wet and cold, between November and February. This timing allows for the roots to establish before the warm and sunny growing season.

When planting:

1. Plant into a hole as deep as the pot and plant the tree collar at the level of the soil (at the point where the roots join the stem). Fill in the hole with soil and push down the soil as you go to reduce the air pockets in the hole.
2. Spread mulch (bark chips or leaf litter) a few inches thick around the base of the tree after planting. Leave a small gap a few inches wide between the mulch and the stem to allow the tree to breathe. Weed and mulch around the base annually until the tree has a chance to grow taller than the surrounding weeds.
3. If you have wildlife like beaver and deer in the area, it’s a good idea to add a cage or tube around the tree for protection for the first few years. The tubes are also a great solution if you’re worried about stepping on or mowing over your new tree. Search for “seedling protectors” from forest supply companies online.

Keep an eye on your tree as it grows and water as necessary during the dry summer months. Smaller trees with healthy root systems (full of small fibrous roots) can survive without watering. Counterintuitively, large trees (those more than a couple feet tall) may need more help and more water in the first few summers in order to support their larger root system.

Starting an oak from an acorn

There’s no cheaper and more fulfilling way to plant an oak tree than to start one from an acorn. You will have the most success if you follow the natural oak cycle: collect acorns in the fall and put in the ground right away while it’s cold and wet outside. Be aware that acorn production has a natural ebb and flow, some years the forest floor will be full of acorns and other years it may be difficult to find even one. All the trees across an entire region will experience this phenomena, an amazing evolutionary tactic that we have many theories about ranging from pollination tactics, the spring weather, and the tree trying to outsmart pests and predators. No matter the cause, the result is that some years you may not find enough acorns to grow and will have to wait to try another year (or work that much harder to find a handful to grow).

Essential supplies for acorn growing: oak acorns, pot, bucket to float the acorn(s), potting soil & caging/protection.

5 Steps for Planting Acorns

Collection: Gather your acorns between September through November directly from an Oregon white oak tree. Make sure you’re collecting from a healthy looking Oregon white oak tree (look for the round lobed leaves and round tree canopy).

Checking health: Once you’ve gathered your acorns remove those that have holes, a sign of insect damage. You can put the acorns in a bucket or jar of water overnight. The acorns that float are probably damaged and you can toss in the compost. Those that sink are ready for germination.

Potting: You can plant your acorns immediately after soaking them. Place them in a long treepot or 1 gallon nursery pot (search online for these or ask a local nursery). Fill your pot with an even mixture of outdoor soil (ideally from under an oak tree) and potting soil. Put the acorn sideways, 1/4 inch below the level of the soil and cover with soil. Cover the top of the pot with wire mesh or some form of breathable protection to keep critters away. You can expect a sprout to form in the spring. Keep the sprout protected and potted for a year or two, watering regularly in the summer.

Planting: After the seedling is two years old it’s big enough to plant outside. Look to our tree planting guidelines above for tips.

Storing: If you’re not ready to plant your acorns right away, dry them off and stick them in a fridge until you’re ready to plant. It’s best to plant within the same growth year (i.e. acorns collected in November should be planted before the following summer).

Have questions about planting and caring for oak? Tualatin SWCD is happy to chat with you about Oregon white oak habitat in our region. Give us a call at 503-334-2288 or email us at habitat@tualatinswcd.org.