31/10/2015 at 14:52
Wow. You maybe have the world's most northernly nectarine. I don't have a nectarine but I do have other citrus trees and mine spend their winters indoors.
I find that they don't really respond very enthusiastically to being pruned. If yours is in no danger of being blown down I'd leave it alone. It sounds as if it has just found its feet.
Good luck next year.