Answer: Sometimes a peony will refuse to bloom if it is planted too deeply, meaning the eyes are deeper than an inch or two beneath the soil surface. This can happen especially if the soil beneath the new plant settles more than expected over time.
Another possibility would be that it has failed to root out into the surrounding soil for some reason and is thus stunting itself. This can happen if there is a rock, tree root or other obstruction hidden underground, or, if it was container grown, if the roots have grown in a circle in the shape of the original pot.
In either case, you could try lifting the plant late this summer, inspecting the possibilities and resetting it. Late summer to early fall is also the preferred time to transplant it if need be, early spring is the second best time to do it.
I hope this helps you trouble shoot the problem.
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