Thanks for the question. It sounds like this tree has looked fine in the past (no powdery mildew or bacterial blight on the leaves) and now has not leafed out completely this spring. Most likely the tree is stressed and in decline due to the drought we have experienced the past few year. Be certain to give it a good soaking of water during dry periods and it will likely recover. If those branches don't leaf out in the next few weeks, any dead wood can be pruned out.

Paul

Tree Care Advisor volunteer