I don't have an answer for you, but will reassign yur inquiry to an agent who specializes in growing hazelnuts.
While you wait for a response, you might read the following publications:
- Growing Hazelnuts in the Pacific Northwest: Introduction https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9076.pdf
- Growing Hazelnuts in the Pacific Northwest: Orchard Site Selection - https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9076.pdf
Birkemeier Nursery in Canby sells bare-root filberts at a very reasonable price. Thank you so much for the links to OSU's information, this will help ensure that my little darlings thrive!