Last year I pulled up azalea plants and planted 8 Green Gem Boxwoods to my front yard flower garden in front of the porch. Four days ago, I replaced three of those boxwoods because throughout the year the leaves had turned yellow and then the whole plant seemed to dry out. I live in Alabama where it get really hot during the summer but I water occassionally and use Miracle Grow on them every other week. The boxwoods that I replaced 4 days ago have already started to turn yellow on the top part of the plants leaves. Even the ones that did not need replacing are starting to turn yellow on the leaves. What could be causing this?? Is it root rot? Below the dirt surface our dirt gets to be thick and holds moisture but its about a foot or maybe a foot and a half below the surface. Should I pull these new boxwoods up? If it's root rot what do I get rid of it? Along with the replacement boxwoods I also planted Midnight Wine Weigela plants. Should these be pulled up?