I have a male and female pistachio tree. Both are grafted trees. At the base of the tree, on the rootstock, it buds and produces new branches and leaves 6 to 12 weeks ahead of the grafted section of the tree.
I have been allowing the rootstock branches to continue to grow until the grafted section buds. Then I cut it back. I'm not sure if this is the right strategy and perhaps it's delaying the grafts from budding and growing. I've been thinking of the rootstock branches as nurse branches keeping the tree healthy and alive. They may be taking energy that might have allowed the grafts to bud earlier.
What is the correct strategy here? i.e. is there a case when you'd allow the rootstock to grow in this situation?
(A quick aside: I have allowed the rootstock on some apples to grow so that I can cleft graft new varieties onto those branches. With the pistachios above I have no intention of grafting anything new onto them so the rootstock branches aren't needed for this.)