I bought (a tiny) one of these at the montreal botanical gardens years ago, and the last 2 or three years it has become a nice bush. I was delighted to find last year, and this, that its leaves are stunning in the fall. this summer i saw a great deal on the same bush at wal-mart and bought one. it is planted near the original, but while the established bush has lovely red leaves, the new one's leaves are still green, and it looks like they may not turn at all. what gives?