I thought this was cool. I got this nectarine tree at a discount store for almost nothing. It had a couple leaves still and barefoot in August. I planted it in this pot and sowed a bunch of snow peas in the pot. I enjoyed many stir fries and a couple of months later as the rest of the leaves started falling off the other prune and peach seedlings next to it the nectarine started growing like crazy. The prune and peach didn't get and peas. This picture was taken on December 25th near Seattle. It's not been freaky cold. But it's gotten well below freezing many times and there's snow on the leaves now. None of the other fruittrees I have still have any leaves left on the branches. Maybe the nitrogen fixer has some anti freeze magic in it as well. Ordering alot more peas and beans next year. I didn't save enough too replant under all my trees.
You may have a problem with peach leaf curl which is so pervasive in this area. My solution has been to put a high tunnel over them made from the frame of a portable garage. The infection spreads in the mist from tree too tree so by keeping them dry they don't get infected. They are close enough to the north side that they get watered by the rain running down the wall. One frame is just right for 3 trees.
What has happened there is that the snow peas have died and their nodules are being tapped by the tree which is making use of the N and other nutrients the peas were holding, that gave the tree the opportunity to have a growth spurt.