From the plant's perspective, the peony seed pod is the culmination of its reproductive cycle. After the energy-intensive process of producing its showy blooms to attract pollinators, the fertilized flower begins to form the seed pod (follicle). This structure's sole biological purpose is to protect the developing seeds and, upon maturation, facilitate their dispersal to grow new genetically unique peony plants. The plant directs a significant portion of its energy and resources into maturing these seeds, which is its fundamental drive for existence and propagation.
The critical consideration for the plant is resource allocation. The process of ripening seeds is metabolically expensive. Energy in the form of carbohydrates, produced through photosynthesis, is diverted from other functions—primarily root and storage organ development—to the maturation of the seeds within the pod. If the gardener's goal is to strengthen the existing plant for vigorous growth and flowering in the subsequent season, allowing seed pods to develop can be counterproductive. The plant's energy is invested in future offspring rather than in fortifying itself.
Removing the spent flower heads before seed pods begin to form, a practice known as deadheading, signals to the plant that its reproductive mission has failed. In response, the peony ceases energy investment in seed production and redirects its resources downward. This energy is channeled into the plant's root system, specifically into expanding and strengthening the storage tubers and forming new eyes (growth buds for next year's stems). This results in a larger, more robust plant with greater potential for impressive blooms in the following spring. For the plant, this is a survival strategy, strengthening its own structure to ensure its perennial success.
There are specific botanical reasons to leave the seed pods on the plant. The primary reason is if you wish to harvest the seeds for propagation. The pods must remain on the plant until they are fully mature, typically changing color from green to brown and beginning to split open slightly along their seams. This indicates the seeds inside are ripe and viable. Furthermore, the structural seed pods can provide winter interest in the garden. From the plant's viewpoint, being allowed to complete its full life cycle is its natural state. However, it is important to note that peonies grown from seed are not true to the parent plant and can take 5-7 years to flower, representing a long-term genetic investment for the plant.
The formation of next year's flower buds occurs shortly after the current season's bloom period. This process is heavily dependent on the plant having ample energy reserves. When seed pods are left to develop, they compete directly with these nascent flower buds for resources. Consequently, a plant that expends energy on seed production may produce fewer or smaller flowers the following year, as its energy reserves were partitioned toward reproduction rather than its own renewal. The plant prioritizes genetic dispersal over its own floral display.
