Let the shoots grow several leaves then pinch or cut back to two or three leaves. If you cut a shoot which is immature it may very likely die back. Defoliation is well done on Maples, Liquid Amber, and Ginkgo to accomplish smaller, healthy secondary growth. Don't plan to do any repotting during these warm months. Don't forget the battle of the ants.
Summer heat encourages the growth of powdery mildew.
This unsightly fungus will attack most leaf surfaces on Japanese or Trident Maples, Elms, Fruit trees, Liquid amber, Crepe myrtle, Roses and many others. Minimize the spread of fungus infections by providing uncrowded bench conditions. The free passage of air between each tree is most helpful. If space is a problem, you should at least rotate each plant to allow exposure to air as much as possible. Spacing will also help minimize insect infections.