Answer: Ideally, peonies are transplanted in the fall, although they can also be planted in the spring. Bare root peony "eyes" would normally be planted in very early spring while still dormant, or would be grown in a pot as a container plant and acclimated to the outdoors, then planted in the garden. Peony shoots are normally up several inches in midspring and withstand frosts, but since yours have been inside and are very tender, you will have to be carefuly about conditioning them gradually to the weather (both real sunlight and cold) before you can plant them in the garden.
At this point, keep them in the brightest location you have and set them outside in a sheltered location once the weather begins to warm. Slowly move them into a spot with sun all day and then plant them in the garden when the danger of frost is past. You will also need to bring them into a sheltered location at night where they will not be exposed to freezing temperatures.
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