The period immediately following the spring bloom is a turning point for perennial peonies. Once the petals fade, the plant shifts its focus from flower production to resource storage, a process that continues for the rest of the growing season. Successful care during this transition is directly tied to the vigor of next year’s display, as the plant must build and store enough energy to survive winter and produce abundant flowers the following spring.
Immediate Care: Deadheading Spent Flowers
The first step after the peony flowers have finished is deadheading, which involves removing the spent flower head and the short stem it sits on. This practice serves both aesthetic and biological purposes. The primary goal is to prevent the plant from wasting energy on producing seeds, which diverts carbohydrates and nutrients away from the roots needed for next year’s growth.
To deadhead correctly, use clean, sharp shears to cut the flower stalk just above the first strong, healthy set of leaves. This ensures the maximum amount of foliage remains on the plant to support photosynthesis. The main leafy stems must remain completely intact now, distinguishing this action from the full cutting back done later. Removing the decaying flower heads also improves appearance and helps reduce the chance of fungal diseases.
Mid-Summer Care: Maintaining Healthy Foliage
After deadheading, the focus shifts entirely to preserving the health of the remaining green foliage throughout the summer months. The leaves are the plant’s energy factories, utilizing photosynthesis to convert sunlight into carbohydrates stored in the underground root system. The quality of next spring’s blooms is directly proportional to the amount of energy the leaves successfully store over the summer.
For this reason, the foliage must remain green and intact until it naturally dies back in the fall. Peonies are generally drought-tolerant, but they require consistent moisture, especially during prolonged dry spells when they may need about an inch of water per week. When watering, apply the water directly to the soil at the base of the plant, avoiding the leaves to reduce the opportunity for fungal spores to germinate.
Summer humidity often makes the foliage susceptible to fungal diseases like powdery mildew and botrytis blight, which appear as a white coating or brown spots, respectively. Ensuring good air circulation by planting peonies with adequate spacing helps to mitigate these issues. If an outbreak occurs, the plant’s overall health is best preserved by removing only the heavily affected leaves, leaving as much healthy green tissue as possible to continue the necessary energy production.
End-of-Season Preparation: Cutting Back
The final act of the growing season is the complete cutting back of the peony plant, performed when the foliage has naturally finished its work. This typically takes place in the fall, after the leaves have turned yellow, brown, or been blackened by the first hard frost. The color change signals that the plant has fully withdrawn its stored energy from the leaves and stems into the root system for winter dormancy.
Cutting back too early, while the foliage is still green, prevents this crucial energy transfer and can severely diminish the size and quantity of next year’s flowers. For herbaceous peonies, use clean, sharp pruners to cut all the stems down to approximately one to two inches above the soil line. This leaves only small nubs to mark the plant’s crown for the winter.
The primary reason for this late-season cleanup is sanitation and disease prevention. Fungal spores, such as those from botrytis blight, can easily overwinter on decaying foliage and stems, leading to re-infection the following spring. It is imperative to gather and remove all cut foliage from the garden area, disposing of it in the trash rather than the compost pile, to eliminate the source of these pathogens.