Walnut tree branches dying.

I have a grafted english walnut tree that has several dead branches this year.
It has always done well before.

Does anyone have any idea what is wrong and what I can do for the tree?

Different this year is that we had a late frost that killed off new growth this spring. All my other plants have recovered from that.
Also I usually spray my trees with neem oil and this year I haven’t.
I have been growing horse radish, daylilies and one blackberry plant under it. This year the horseradish has really taken over.

I used to grow tomatoes near it but A couple years ago I stopped planting tomatoes there and am now   growIng blackberries in that bed.

Looks ok maybe dry?  Walnuts are not good for the nightshade family.

Horse radish can spread quite well.