From our perspective as peony plants, the foliage you see above ground is our solar panel and food manufacturing center. Throughout the spring and summer, our leaves work tirelessly, using sunlight to convert water and carbon dioxide into energizing carbohydrates through photosynthesis. This energy is not primarily used for immediate growth; instead, we diligently transport it down to our storage organs—the thick, fleshy roots and the "eyes" (buds) at our crown. This stored energy is the absolute lifeblood for our survival through the winter and, most importantly, for producing those spectacular blooms you admire next spring. Cutting this foliage away too early is akin to removing our ability to stock the pantry before a long, hard winter.
The first frost of autumn is a critical environmental signal for us. It acts as a natural trigger, indicating that the growing season is drawing to a close. The cold temperature effectively halts the photosynthetic process. The chlorophyll, which gives our leaves their green color, begins to break down. This is why you see our foliage turn yellow, bronze, or brown. From a biological standpoint, this color change signifies that we have begun the process of withdrawing the last valuable nutrients from the leaves back into the crown and roots for safekeeping. Our work for the season is complete.
Patience is the greatest kindness you can show us after the first frost. Do not rush to cut our foliage immediately. You must wait until the leaves have fully died back. This typically occurs a few days to a week after that first frost. The tell-tale sign is when the stems and leaves have turned completely brown and have become soft and droopy, collapsing towards the ground. This confirms that the nutrient transfer back to the roots is finished. Cutting into still-green or yellowing stems severs the pathways for this vital energy transfer, robbing us of reserves and potentially weakening our display next year.
When the foliage is fully senesced (brown and softened), you may proceed. Using clean, sharp pruning shears or scissors, cut our stems down to within approximately 2 to 3 inches (5 to 7.5 cm) above the soil level. It is crucial that you avoid cutting too low and damaging the delicate reddish-pink buds (the "eyes") on the crown at the base of the plant, as these are the future growth points for next year's stems. Clean your cutting tools before and after use with a disinfectant like rubbing alcohol. This simple step prevents the accidental spread of fungal diseases or bacteria from other plants in your garden to our fresh-cut stems, keeping us healthy as we enter our dormant period.
All of the cut foliage and any other plant debris around our base should be gathered and removed from the garden area. Do not compost this material near other plants. While we are generally resilient, our dead foliage can harbor fungal spores like those of Botrytis blight, which can overwinter and cause issues when the new growth emerges in the dampness of spring. Removing this debris is a key step in our integrated pest management. Once we are cut back and the area is clean, a simple layer of mulch, such as shredded bark or straw, can be lightly applied over our crown after the ground has frozen. This helps to maintain a consistently cold soil temperature, preventing heaving from freeze-thaw cycles that could damage our roots.
