Care of 100 yr old English walnut trees

Asked May 15, 2016, 6:55 PM EDT

I have 4 huge old walnut trees and they still produce a lot of nuts, but most of them are inedible. Can this situation be improved, or is this what happens when trees become this old?

Benton County Oregon walnut trees

3 Responses

There is a lot of variation in nut quality and flavor in different walnut cultivars. These trees may simply be one of the less favorable varieties. Are you curing them before eating? It helps to let them dry in burlap bags or similar for a few weeks or more and the bitterness will dissipate. Water stress can affect nut quality as well.

The trees are over one hundred years old and are healthy and beautiful. Does nut quality deteriorate with this much age? Yes, I do know to cure the nuts. Walnut husk fly could also be the problem, but my first question concerns the age of the trees.

It is not likely an age effect. If the trees are still producing a crop then they are still trying to reproduce. There could be nutritional deficiencies or diseases affecting the health of the tree enough to affect nut quality. Please consult the following publication and consider performing soil and tissue testing to determine potential deficiencies.

https://catalog.extension.oregonstate.edu/em8907

If the husks and shells are stained black then yes walnut husk fly could be the issue. However, this staining is more of a concern for commercial producers and the nuts are not usually affected.