Help! Two weeks ago I planted 2 Hydrangea paniculata "Tardiva", tree form, next to each other in a mostly sunny raised bed area, I added compost to the planting holes and mulched the area with a pine mulch. The leaves of one are beginning to turn YELLOW!!! Am I losing the plants, are they shutting down due to the drought here in NJ, could it be transplant shock??? Shouldn't have planted in August! Need some advice. Thanks!