Pruning and Thinning 4 in 1 Pear Tree
I have a few questions about my 4 in 1 fireblight resistant pear tree.
The main question is how to prune to maintain balance. I have 2 vigorous grafts and 2 wimpy grafts. I think I am keeping the center open pretty well so far. I understand that I need to try to balance the 4 grafts. Does that mean keep them all about the same height? Same total mass? Or, is there some other measurement to follow. The two lower grafts are the more vigorous--Keiffer and Warren--are on the north side of the tree, and tied down to about 60 degrees. The Harrow Delight and Blake's Pride are more vertical. They seem happy, just more pokey growers.
Second question: one graft, the Keiffer, set some fruit this year. Does it need to be thinned to one fruit per cluster?
Third question: There is a mystery fifth graft on the tree. Should I chop it off, or wait to see what happens?