I use FP 9-3-6 for all my trees.
When maples start to push growth in spring, each bud breaks to push a short internode before the next pair of leaves appears. The next internode is usually extremely long, up to 6" or more, except on cultivars known for very short internodes. Look at your trees to confirm. This is a serious problem with regard to how it affects the form of your plant. In short, it wrecks it. Your trees should be pinched as soon as the first pair of leaves can be separated far enough to allow a pair of scissors to get at the internode. This results in 2 maturing leaves and a pair of buds in each leaf axil. As soon as the new growth starts moving in the new leaf's axils, you should remove the first pair of leaves that occurred after bud break. Not to worry, the tree will back-bud automatically and replace those leaves. When new leaves appear after the first pinch, pinch again immediately. The best time to fertilize is when most of the second sets of leaves are mature or almost mature. If you fertilize too early, you get a lot of long, rank growth that doesn't do anything for your composition.
Pinch the central leader where the pencil points as soon as the 2 leaves opening can be teased apart with the tip of your scissors to get at the central leader.
You'll get a new branch from the axil of each leaf that remains. When the new branches are evident, remove the 2 leaves you see above. When the 2 new branches have pushed the next set of leaves, pinch again. After that, you can use defoliation techniques to slow down the overly strong branches so the weaker branches get their share of the energy. If you see a branch high on the tree that's thicker than other lower branches, remove 1 leaf from every node to slow it down and force energy to other branches. Build your trees from the bottom up. Maples want to put 2/3 of their total energy supply into the top 1/3 of the plant, so you can build a top any time you want. Best to do it after your lower branches are formed.
Al
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Pinching growth for shape and growth
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