When to cut peonies after bloom?
When peonies have finished blooming, the flowers will turn brown and wither and over time the faded flowers will fall off the plant. The green stems and leaves then remain standing with their leaves and seed pods form in place of the fallen petals.
You can harvest the seeds late summer / early fall and from there you can grow your own peonies. Mind you, it takes about 3-5 years before you have a fairly sized plant with flowers. If you want to know how to grow peonies from seed, at Willow Garden they can tell you more.
The peony stems and leaves will eventually turn brown and wither. You could leave this around the plant. In the end, they are simply absorbed by the soil and they still contain many valuable nutrients for the entire plant to use next season. After all it’s still organic matter that helps in maintaining a healthy soil. After the winter, before the plant starts sprouting again, you can remove the plant debris before the plant stems start growing again.
If you are concerned that the plant may become susceptible to certain fungal diseases, you can cut the withered stems of the herbaceous peony and toss it with the compost once they are brown and dry. Fungal diseases like powdery mildew or botrytis blight weaken the plant and grow well in moist conditions. It not only harms the plant but may affect the whole peony plant potentially leaving it with diseased leaves and not so pretty flowers. Although, healthy peony plants may not be affected by these disease problems as easily as younger or weaker plants, it’s still wise to apply proper peony care.
What about the spent flowers? You could deadhead peonies after their bloom to keep the peony plant looking pretty and neat. With sharp pruning shears cut below the flower head and add it to the compost pile.
So, let’s come to he point here. When do you cut peonies after flowering? You basically leave the peony alone at the end of the season. You don’t have to cut anything, the main reason being that you want to give the plant time to store nutrients from the stems and leaves in the roots for the cold winter ahead. Although the peony can withstand cold well, take care you ensure that it has sufficient reserves for creating next year’s flowers.