Mastering the Climate: Growing Disease-Resistant Nut Trees in the PNW

Living in the Pacific Northwest means embracing a climate of contrasts. 75% of the year, we have steady rain that nourishes - or floods - our landscapes. Come June, the rain clouds fade away for months as the dry, sunny spells of summer take over. These two different extremes create a unique challenge for PNW gardeners.

It's important to keep our all-or-nothing rainfall in mind when planting nut trees. Many standard varieties that are recommended as "easy" in other parts of the country actually demand precise care and attention to thrive under our diverse conditions.

In this article, we’ll look at the solution to this problem - disease-resistant nut trees that actually thrive in the PNW. With a mix of my personal experiences and local expert insights, we’ll figure out what will help your nut trees to flourish in your backyard.

Quick Tips:
1. Ensure well-drained soil for young nut trees.
2. Use mulch to retain moisture.
3. Select late-blooming varieties to avoid frost damage.

My Journey with Nut Trees: Overcoming Regional Challenges

When we thought about nut trees for our own small orchard, we figured that drought-tolerant varieties would be our ticket to success. However, the reality was that there was more to the picture than our dry summers.

• Early Watering Needs: Even drought-tolerant nut trees like hazelnuts need ample watering in their initial years. We had to adjust our approach after some of our hazelnuts did not fair well after a heatwave during a drought.

• Wet Winter Woes: Chestnut trees are known to struggle with the region’s wet winters. We are experimenting with keeping them in pots for their first few years so they can always be in well-draining soil.
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• Unpredictable Temperatures: We had an unusually cold period this past March, which may be the cause of death for one of our hazel trees.

Adapting to the unique climate of the PNW and implementing the right care techniques is starting to give our nut tree plantings a better chance of success.

Root Rot and Fungal Diseases:

Nut trees like walnuts and hazelnuts are particularly susceptible to root rot in wet conditions. Ensuring well-drained soil is crucial, especially in areas with heavy clay.

How do you know if your nut trees have root rot or a fungal issue? Here's what Oregon State Extension tells us to look for:

• white stringy growths beneath outer bark (mycelium)
• cankers on upper branches
• sudden leaf drop or death in summer
• white oblong fungal growththat turns black (stroma)
• bark discoloration
• damaged branches and trunks

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Criteria for Our PNW Nut Tree Selections

Nut Tree Cultivars to Avoid in the PNW:

• Nevada Chestnut - not blight resistant
• Almond - All-in-One - susceptible to fungal disease
• Any Almond - not drought tolerant, late frosts cause damage, doesn't do great in clay soil

(Burnt Ridge, Cloud Mountain Farm)

Tips for growing healthy nut trees in the PNW

• Burnt Ridge reminds us that you’ll need two varieties as hazels need to cross pollinate; double-check that your varieties will be in bloom at the same time and that they are compatible.
• Hazelnuts will produce healthy crops in areas where temperatures do not get below 15 degrees, according to OSU.

New Developments against Hazelnut Weevil

Researchers are exploring the use of entomopathogenic nematodes as a biological control method for the hazelnut weevil.

‍These nematodes are harmful to insects, but don't impact the tree (entomos is Greek for insect, pathogenic is something that causes disease).

This approach is more environmentally friendly than the alternative of chemical pesticides. The results are great too, with up to a 75% weevil mortality rate!

Chestnuts and agroforestry

Chestnuts make an excellent addition to agroforestry systems. Jeremy Kaufman is the Chief Operating Officer for Propagate, a company that helps farmers to integrate more trees into their land. He says, “through our work to date, we’ve discovered that chestnuts are the perfect complement for crops in agroforestry systems." Even if you're not a farmer and have an urban garden, the benefits of chestnut trees are still substantial. Kaufman notes that chestnuts are known to boost soil health while decreasing erosion. They are also renown for their carbon sequestration abilities, making them an excellent choice for regenerative gardeners with some space to spare.

Strong + Resilient Trees for a Spray-Free Organic Home Orchard

As a regenerative organic gardener, it's important to me to maintain a spray-free orchard. In my backyard, that also includes organic-approved copper spray.

Organic orchard practices are especially important in the PNW, where the rains can wash pesticides, synthetic fertilizers, and fungicides into our water ways.

This is why it's important to not only choose disease-resistant varieties, but to also follow these guidelines for healthy nut trees.

Promote healthy growth:

• try to avoid drought stress in first 3 years
• add mulch around base of tree (do not make a volcano, though!)

Careful Monitoring and Maintenance:

• a stitch in time saves nine - or, pruning off a diseased branch can help prevent tree failure
• follow a regular pruning schedule
• be extra vigilant after heavy rain seasons or during extra dry summers

You can grow nut trees here!

Growing nut trees in the Pacific Northwest has taught me a lot about best practices for success. While I'm still waiting to see the fruits...or nuts...of our labor, I know that these trees will support me on my quest to be more self-sufficient.

I hope my experiences can offer some guidance and encouragement to fellow PNW gardeners.

Further Resources

Anne of All Trades Tree Planting Guide

Growing Hazelnuts with Burnt Ridge Farm's Micheal Dolan

Harvesting Chestnuts with Burnt Ridge

The Elusive White Walnut by Indefense of Plants

George Bush, the first African-American settler in Washington State, and his historic Butternut Tree