Blue Oak (Quercus douglasii)–Trees of Sonoma County, CA

The Blue Oak, or Quercus douglasii, is a majestic tree that is often found in the dry, hot regions of California, but we also have our fair share of them in Sonoma County. Known for its beautiful blue-gray foliage and impressive stature, the Blue Oak has been a beloved fixture in the state for centuries. Being a native oak, the Blue Oak also plays a vital role in the ecosystem, providing food and shelter for a variety of animals and helping to maintain the health of the surrounding environment.

General Information:

Scientific Name: Quercus douglasii

Native to: California

Mature Size: 20-80 feet tall and wide

Growth Rate: Slow

Ideal Planting Location: Full sun, well-draining soil

Water Requirements: Blue Oak is drought tolerant and can tolerate low to moderate water levels. However, it will benefit from occasional deep watering during periods of drought.

Common Pests and Diseases:

Blue Oak is generally resistant to pests and diseases. However, it can be susceptible to oak root rot and mistletoe. To prevent these problems, maintain good tree health by avoiding damage to the tree’s roots and trunk, and promptly treat any signs of pest or disease infestations. Mistletoe should be removed when it is seen as it can quickly spread to the rest of the tree and to neighboring trees.

Additional Care Tips:

Mulch around the base of the tree to conserve moisture and suppress weeds.

Prune to remove dead or diseased branches, improve air circulation, and promote healthy growth. Structural pruning when young. 

I hope you learned something about the trees we live amongst in Sonoma County! At LongView Tree Care, we are passionate about providing high-quality tree care services to our clients. If you’re in need of tree pruning, tree health care services, or hazard tree removal, we’re here to help. Contact us today to learn more about how we can help you maintain the health and beauty of your trees.