I purchased 3 Japanese blueberry trees. They came on a 25 gallon container and replanted on a 60 gallon planters. After 6 or 7 months one of the trees started losing leaves. I noticed that the leaves started diyng off from the tip. Eventually it died completely. So I lost the first one. Now the second tree started developing the sames condition. It was beutiful two months ago but now i don't know if it will survive. I water the trees every week. I don't think is lack of water. Bedsides,I water all the trees at the same time and one was fine and the other died. Any idea whats wrong with my trees?? I live in Miami btw.