I have a fern leaf Peony that, after I transplanted it to a sunnier spot, now only grows about four inches tall and doesn’t bloom.
Why? From my mother’s garden, who has passed on. Planted in richer soil than before. Formed buds that didn’t develop. Used to grow 14-16” tall.
Certified GKH Gardening Expert
It may be too fertile of a spot. Too much nitrogen can cause a lack of blooms, but so can transplanting at the wrong time.
These will have a very similar care to a standard peony. These articles will help: