Cut off withered and fertilize lightly
Once the peony's flowers have wilted towards the end of flowering (late June), they should be cut off to prevent seed formation. To do this, use secateurs to cut off the flowers and the stems. You can then easily fertilize the plant.
Do you want the peony to develop seeds in order to use it for propagation? Then don't leave all the flowers standing, just one or two. The seeds that grow there are enough for sowing.
Tips
If you never remove the flowers after they are in bloom, don't be surprised if your peony doesn't bloom at all after a few years.
