I planted these two pomegranate trees 3 years ago. They have been growing very vigorously until we had that last frost in early April. It didn't seem to bother one of them other than burning the brand new growth a little, but the other didn't recover. I used a mild fertilizer like I do every year in April. I don't think the problem is related to the cold. Any ideas what is wrong? I'm in 8B Pensacola, FL.