I have 3 willow oak trees in my yard that were planted by the builder 5 years ago. They also planted willow oaks in the adjacent neighbor's yards as well. For some reason, 2 of my trees have no leaves yet (they do have buds) and the other tree has leaves on the bottom and buds on the top. The trees in the neighbor's yards are completely covered with leaves (have been like that for a couple of weeks).

Is there anything I can do to get the trees to open their leaves?