The genus Lilium are beloved garden bulbs known for their spectacular flowers and vertical structure. Gardeners often face the dilemma of moving established plants. While relocating lilies during the peak growing season is sometimes necessary, summer transplanting is strongly discouraged for the long-term health of the bulb. Moving a lily while it is actively growing and flowering is possible, but it introduces significant stress and risk to the plant.
Why Summer Transplanting Is Risky
Transplanting lilies during the summer months coincides with their period of maximum vegetative growth and energy expenditure. The plant is actively producing stems, leaves, and flowers, a process that requires a substantial amount of stored energy and water. Disturbing the root system at this phase forces the lily to divert energy from flowering and growth toward root repair, which can compromise its vigor.
The combination of warm weather and root disturbance increases the risk of heat stress and moisture loss. When roots are damaged during the move, their ability to take up water is temporarily impaired. However, the large amount of foliage continues to lose moisture rapidly through transpiration. This imbalance leads to transplant shock. Lilies that survive a summer move may not bloom again for a year or two as they focus on rebuilding the bulb and root mass.
Emergency Steps for Moving Lilies in Warm Weather
If circumstances demand that a lily be moved during its active summer growth, careful preparation and handling can maximize its chances of survival. Begin by deeply watering the current location the day before to ensure the soil clings to the root system. Before digging, significantly reduce the foliage to manage the transpiration rate, cutting the stem back by about one-half to two-thirds.
The digging process must prioritize preserving the entire root ball intact, as root exposure to air is damaging. Dig widely, starting about 5 to 6 inches away from the stem, and deeply (at least 12 inches) to fully encompass the bulb and its anchoring roots. Carefully lift the entire soil-and-root clump and place it immediately into a container or on a tarp for transport.
The new planting site should be prepared ahead of time to minimize the time the roots are out of the ground. Dig a hole slightly larger than the root ball, setting the lily in at the same depth it was previously growing. After gently backfilling the hole with loose soil, water the plant just enough to settle the soil around the roots, but avoid overwatering, as saturated soil can lead to bulb rot.
Post-transplant care involves providing heavy shading for the first week to reduce heat and light stress on the compromised plant. Monitor the soil moisture daily, allowing the top two inches of soil to dry out before watering again. If lower leaves begin to yellow, it indicates the plant is receiving more moisture than it can handle, signaling an immediate need to withhold water until the soil dries.
When Is the Best Time to Transplant Lilies?
The optimal time to transplant true lilies is when they enter a period of semi-dormancy, typically in the late fall or very early spring. Late fall is preferred, occurring after the foliage has naturally yellowed and died back, but before the ground freezes solid. This timing ensures the plant has completed its cycle of storing energy in the bulb for the next season.
Moving the bulb during this resting phase minimizes shock because the plant is not actively pushing out new growth or flowers. The cooler soil temperatures encourage root establishment without the high transpiration demands of summer heat. The bulb can focus its remaining energy on growing new anchoring roots throughout the fall and winter, preparing it for vigorous stem growth the following spring.
To move dormant bulbs, cut the faded stems down to just a few inches above the soil line and carefully lift the entire clump. Once out of the ground, the lily can be divided, separating any smaller offset bulblets from the main bulb. Plant the larger bulbs about five to six inches deep, while smaller bulblets only require a depth of two to three inches, and ensure they are replanted promptly so they do not dry out.