high grafts, pruining the rootstock ?
I planted Siberian crabs and let them grow 5 years. I then grafted the main stems 3 to 5 feet high, leaving some of the rootstock limbs as insurance life. the grafts have done well. I have kept this rootstock growth under control, and low. I'm wondering if my continual controlling of this low growth is invigorating my top good apple limbs. they are growing well, but not fruiting. I have learned to stop pruining for vigor on the tops, but wondering if this low rootstock trimming is haunting me somehow? I hoped to leave the brushy trunk of the rootstock so the deer won't rub their antlers on them and kill the tree. they have killed a bunch of my stuff that way and I'm getting to old to start over!
we also have bear trouble here. they tear off entire limbs. last year I replaced a limb that the bears tore off. i used a grape technique like a t-bud, but added a 6 inch two bud scion, assuming I could train it away from trunk, if it grew. it did grow, but poorly. i hope it takes off this spring to fill out this scaffold.
the real question...will trimming this low rootstock continue to invigorate the top of the tree? ( they are limbs, not suckers)