I have a question about "full sun" fruit trees.

Do they have to be in full sun all year, or only during spring and summer?

I'm thinking of moving some dwarf fruit trees we bought last spring and just put in the ground to keep them over the year to the north side of my home. In late December/early January, it's shady about 10' away from the structure, but by May it's only shady about 2', and by July, it's only shady inches from the house.

When I lived in my old home, I had a bank of lilacs along the north side and they bloomed every year even though they're supposed to be in full sun. I would assume the same for the fruit trees, but because they bear fruit as well as flowers, I'm wondering if they need direct sun all year.

Thanks in advance for any wisdom!