Answer: In a word, yes. There would be seeds inside as with any flower. Usually gardeners will trim off the spent flowers as soon as they fade, not only to make the plant look tidier but also to reduce the chance of fungal or bacterial infection starting on the decaying blooms. Peonies are somewhat prone to foliar problems so it is a good habit to get into. Too, peonies are usually propagated by division rather than by seed to assure that the new plants are as nice as the originals.
Q&A Library Searching Tips