We are in Chicago, we just purchased 2 bushes I believe are Blue Princess around Fathers day. They did wonderful outside for a couple months. Then Mid July some leaves were turning yellow and falling off. Then Leaves started to turn brown and fall off. I just dug up the tree and roots appear to be healthy. I've searched the tree for any signs of bugs (nothing). 2 days ago spoke to someone and they said to try cover for plant which was a form of spray, which will allow leaves and plant to hold in moisture. Scrapped a couple branches here and the trees seems to be green. Gave the trees also acid fertilizer (Mircale Gro). How soon will new leaves sprout? Im not sure if im just not giving enough time for the revival or is there more to the problem? Ask 2 other boards they could not help. These plants are also potted in very enormous potters. (with holes for drainage.) Any help will be appreciated.