I recently purchased a bare root Japanese zelkova tree online. It came with the leader pruned back. The whole tree is barely 2' (60 cm) tall at this point. I've found in some cases that nothing will grow upward from that point. Is there any way I can notch or cut the top at an angle to promote growth upward?
My take on this would be to do nothing immediately, but wait for it to show signs of active buds. Apical dominance is very strong and the leader will want to go up. As soon as you can see buds breaking prune right above the topmost and when the lower ones are large enough rub them off leaving the leader as the only shoot. The leader should soon be vertical and establish the framework. It might not be immediately upright; there may appear to be a slight crook at first, but this will only last a few years - as the tree gets larger and broader the bend will become less pronounced until you can't see it. Keep rubbing off lower buds to ensure that all the growth goes to the single leader for the first few years.