I planted a plum tree that has 5 different varieties grafted onto it in November 2021 and am in the process of fan-training it, as I don't have enough room in my yard for a full sized tree. I'm not sure how to prune the tree, as I'm not sure whether the fruit grows on spurs, etc... The varieties are green gage, brooks, Stanley, Seneca and yellow egg. I just started to train them on cables and bamboo sticks in the fall of 2022. I'm enclosing some pictures, and am looking for advice as to what I should prune out. The tree is not very balanced because of the grafting. 1. I need to shorten the longer branches. How much do I shorten them? 2. Are those shoots I see water sprouts? Do I take them all off? 3. This video on a fan-trained peach says to remove all the leaf buds except for the ones you want to use as replacement branches for next year's fruits. If that's the case, it would appear that I would have to remove almost all my leaves.
