"How deep do you plant your Itoh peonies?"
Itoh Peonies are intersectional peonies. Toichi Itoh is credited with being the first hybridizer to successfully cross a tree peony with an herbaceous peony, resulting in an intersectional peony. Since these peonies are a cross between tree peonies with woody stems and herbaceous peonies with herbaceous stems, the stems of intersectional peonies are semi-woody. These stems can be left on the plant and cut back to the lowest bud or be cut off completely. This picture is of intersectional Peony 'Bartzella' whose stems were cut back to above the lowest bud. I have drawn a line on the picture to show the proper planting depth for this type of peony. The stems (above the red line) face up towards the sun, and the roots (below the red line) should be planted below ground. So the proper planting depth for intersectional (Itoh) peonies is right at this joint between the stems and the root. If your intersectional peony does not have any above ground stems, then I would recommend planting the roots below the soil with the eyes or buds facing up towards the sun. The eyes or buds should be even with the soil level or just below the surface of the soil.