Just following on this....I have basically the same story with mine. I bought two Black diamonds 3 years ago. This year, even with our mild winter, one was very late coming out. And where the first one leafed out along the woody branch, the late one came out from the bottom and the leaves are not nearly as dark as they always have been, or as dark as its used-to-be twin. Has any information come to light? P.S. I live in TN, Zone 7.