When we moved from our last house, I took a cutting of a peony that my late mother had bought for me and threw it into a pot. Last summer it flowered beautifully on my deck. I've put it into a corner to protect it during our harsh winter here in Pennsylvania. I want to plant it out in my garden this spring but I don't want to kill it. Should I wait for the fall or until it's finished flowering? Please advise. Many thanks!