I have a peony that, while comes into bud, never fully opens. The plant is approximately 4 years old (or more) and has been in the same location for that time period and the flowers have never fully opened. I have looked to see if there are any insects / bugs on the plant (other than ants) and have found nothing. I have looked at the soil conditions, although the two peonies on either side of this one, open fully. Do you have any ideas on what this might be. Thank you, Jane (E. Boekholt)
There could be a few reasons your Peony does not flower, this article will help you.