I have two purple potato bush trees in my front yard located on different sides of the house. These trees were already planted when I moved in five years ago. They were both doing well but suddenly one of the trees has lost most of it blooms, leaves turning yellow and appears to be going dormant. I have been watering them as needed and starting using Miracle Gro Plant Food (15-30-15) for about 2-3 months. I do not have a green thumb and I have not had to take care of a yard before. I appreciate any advice. Thank you