Asters are perennial plants known for their daisy-like flowers, which provide vibrant color in the late summer and fall garden. Successfully moving these plants requires careful attention to timing, as this directly impacts the plant’s ability to recover and establish itself. A well-timed move minimizes transplant shock and ensures vigorous growth and flowering. Transplanting is often necessary every few years to rejuvenate older, overcrowded clumps that show diminished central growth.
Optimal Seasons for Transplanting
The best time to transplant asters is in the early spring, just as new green shoots emerge. Moving the plant before it dedicates energy to top growth allows it to focus resources entirely on root establishment in the new location. The cooler air and soil temperatures of spring, combined with higher moisture levels, create an ideal low-stress environment for recovery. This timing ensures the new divisions have the entire growing season to develop a strong root system before summer heat or fall flowering.
Asters can also be successfully transplanted in the early fall, but this window is much narrower and riskier. Fall transplanting should occur immediately after the plant has finished flowering, but at least four to six weeks before the first expected hard frost. Transplanting during the high heat of summer or when the plant is actively blooming should be avoided, as the combined stress significantly reduces survival rates.
Necessary Preparation and Division
The new location should provide full sun exposure and have soil that is rich in organic matter and well-draining. Dig the new hole two to three times wider than the root ball, but only as deep as the root ball itself. Incorporating compost or aged manure into the surrounding soil helps condition the area for rapid root growth.
To prepare the plant for the move, cut back the top growth and stems by approximately one-third to reduce the foliage the damaged root system must support. Use a sharp spade to carefully dig around the perimeter of the clump, aiming for a wide radius to capture healthy root mass. Once lifted, divide the root ball with a sharp knife or spade, keeping the healthy outer sections with new shoots and discarding the tough, woody center.
Execution and Immediate Care
Gently place the divided section into the prepared hole, ensuring the top of the root ball sits level with the surrounding soil. Backfill the hole with the amended soil, lightly firming it down to eliminate air pockets around the roots.
The most critical step immediately following the transplant is a thorough and deep watering to settle the soil completely. For the first few weeks, the newly planted divisions require consistent moisture to support the development of new roots. Applying a two-inch layer of organic mulch around the base of the plant helps retain soil moisture and regulate temperature. If the move occurred during warmer weather, providing temporary afternoon shade can further reduce stress on the recovering plant.