In my location many of my peony roots are at the surface and the buds for next years flowers are visible through the winter. I never apply fertilizer on top of the plant but do spread it around the plant. When a peony has not bloomed for two years and is mature enough to bloom, I dig it up and replant it. I dug one yesterday and replanted it high to get plenty of chilling through this winter which will assure next springs bloom. Al

Some peonies just take time to bloom. Also the size of the original roots can have a factor. If the roots were small when planted they probably did not have enough nutrients stored to produce flowers. They have to be able to keep the roots alive and well before they risk sending up flowers.

You might want to sprinkle some generic fertilizer 10-10-10 etc around not on top of the roots.

I don't think the depth of your peony is an issue. I agree with castiloga that in warmer growing zones, the buds of the peonies should be visible during the winter. This will allow the roots to get enough chilling hours for flowering.

You did mention that the peony is near a tree. The amount of sunlight that the peony gets during the growing season will also affect its ability to bloom. So it is possible that it is in too much shade, and you may need to move it to a sunnier spot in the garden.

I also agree with maifleur if your peony was a small root just planted 2 years ago, the roots may not yet be large enough to produce flowers. However, if your peony has been in this spot for several years and had bloomed previously, but is no longer blooming, it may be that the tree has started to crowd it and is providing too much shade.

Another consideration that may be worthwhile is the possibility that the Hemlock tree is also competing with the peony for soil nutrients and moisture. Some conifers can really be agressive feeders leaving much of nothing for their neighbors to live on.

Also the manure that you are throwing over the crown of the plant may be introducing botrytis. If this plant is shaded by the hemlock and/or the hemlock is blocking air movement then the residual moisture may be allowing the mold to really take off and cause this plant problems. Even a mild case of botrytis can keep a plant from blooming.

Leon

Peonies need full sun. Plant anything near a tree above ground. Do not hurt tree. Somebody planted peonies under magnolia trees on my property and they did not bloom in that shade. Simple answer.

Not that simple of answer because it is only partially correct. Some peonies are sun plants some are understory.