This spring I purchased a potted tree peony with one bud on it. I planted it in what appeared to be an ideal location, but it looked awful. I checked the soil around it and found it sopping wet, so I moved it thinking it was getting too much water. Now it's not in wet soil and it's still drooping, leaves, and even the bud stem. It's very sad!

What's wrong with my tree peony?

By the way, I have 2 other tree peonies in great shape. They bloomed beautifully this year. Just wondering what I did to make this one so sad.