I'm farther South than you (S. Willamette Valley), but we have half a dozen Walnuts trees on our place.
A few were planted by my grandpa when he was a kid ( he doesn't know the specific variety, but says they are English Walnuts grafted on Black Walnut rootstock). Those are still producing some at 85 years old or so. They get no supplemental irrigation.
We have a fifty-year-old Butternut tree (gets some Summer watering). We hardly ever eat them because they are hard to crack out. But the kids do eat some. Also the hulls make Khaki dye, and I've heard you can pickle the underripe fruit.
I have planted a few new Walnuts that are around eight years old (Idaho Carpathian, Cook's Giant, Rodhouse). They produce modest crops of tasty nuts. But I irrigate them a few times throughout Summer. Last year I OVER-irrigated and broke off a big limb from the Cook's Giant. I also have two seedling Heartnuts (still tiny, but scrappy).
I notice a lot of wild Black Walnuts in the area that get no special attention. Also seedling English-type Walnuts that squirrels plant seem to do fine on their own. I recently colllected a bunch of Black Walnuts and seeded some droughty, sandy ground that will get no irrigation... we'll see how they do.
Good Luck with the Nuts!
Listen to the land.
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