From the perspective of the plant itself, the ideal time for transplanting is during its dormant phase. For the bare root Bleeding Heart (Dicentra spectabilis), this dormancy occurs in late autumn, after the foliage has completely died back, or in very early spring, before any new growth has begun to emerge. During dormancy, the plant's metabolic processes are slowed to a minimum. It is not actively producing new leaves or flowers, and its energy is concentrated within its storage organs—in this case, the thick, fleshy roots. This state of suspended animation is the least stressful time to be moved. The plant is not losing water through transpiration from leaves, making it far less vulnerable to the shock of being dug up, transported, and replanted.
The plant's biology is finely tuned to soil temperature. Bleeding Heart roots begin to grow in cool soil, typically when temperatures are consistently between 40-55°F (4-13°C). Planting during a period when the soil is at or approaching this temperature range is crucial. In autumn, the soil is still warm from the summer but is steadily cooling, which encourages the roots to establish themselves and anchor the plant before the ground freezes. In spring, the cold, moist soil is just beginning to warm, which signals the roots to start growing and absorbing water and nutrients in preparation for top growth. Planting when the soil is too cold can keep the roots inert, while planting in warm soil forces the plant to simultaneously try to establish roots and support foliage, a difficult task that can lead to stress or failure.
A bare root Bleeding Heart must never be planted during its active growth or flowering period in late spring and summer. At this time, the plant is expending a massive amount of energy on producing and sustaining its delicate, fern-like foliage and arching chains of heart-shaped flowers. Disturbing the root system during this phase is catastrophic from the plant's viewpoint. The damaged roots cannot uptake the vast quantities of water required to support the soft, leafy growth, leading to rapid wilting, desiccation, and almost certain plant death. The plant's priority is reproduction (flowering), not survival (root establishment), making it exceptionally vulnerable.
When planted at the correct dormant time, the plant can follow its natural cycle without interruption. A fall planting allows the roots to acclimate to their new environment throughout the winter and be perfectly poised for explosive growth in spring. The plant can allocate its stored energy efficiently: first to root development, then to stem and leaf production, and finally to flowering. A spring planting, done as soon as the ground is workable, achieves a similar result. The cool, wet conditions of early spring naturally support root development without the stress of summer heat. The plant wakes up in its permanent location, allowing its growth cycle to proceed seamlessly as if it had always been there.
