The Bloomerang Lilac (Syringa x ‘Bloomerang’) is a hybrid cultivar known for its ability to bloom multiple times throughout the growing season, a trait that sets it apart from traditional lilacs. Unlike older varieties that produce flowers exclusively on the previous year’s growth, this plant flowers on both old and new wood. This characteristic means the Bloomerang Lilac requires a specialized pruning schedule to maximize its flower production beyond the initial spring flush. Understanding the timing of these cuts is essential for achieving a continuous display of fragrant blooms from spring until the first frost.
Timing the Main Spring Cut
The primary structural and shaping prune for the Bloomerang Lilac should occur immediately after the initial, heavy spring bloom has faded in late spring or early summer. This first wave of flowers is the most prolific, and delaying the cut can negatively impact the plant’s energy cycle for the subsequent rebloom. This main cut serves a dual purpose: to manage the shrub’s size and to stimulate the new growth that will produce the second flowering. When performing this shaping cut, remove no more than one-third of the plant’s overall size to prevent undue stress. By removing the spent spring flower clusters, the plant is signaled to redirect its resources away from setting seeds and toward vegetative growth, which fuels the repeat blooming cycle.
Fostering the Summer Rebloom
The reblooming phase of the Bloomerang Lilac, which begins in mid-summer and continues until frost, is maintained through a process called deadheading. Deadheading involves the removal of individual spent flower clusters as they appear throughout the summer months. This continuous maintenance prevents the shrub from allocating energy to seed development. Use sharp hand pruners to snip off the entire spent bloom, cutting just above the first set of healthy, outward-facing leaves below the faded flower. This light, routine pruning throughout the summer differs significantly from the heavier, structural cut performed after the spring bloom.
Late Season Pruning Mistakes to Avoid
Pruning should cease entirely by late July or early August to ensure the following year’s spring bloom is not compromised. The Bloomerang Lilac, while reblooming on new growth, still sets the buds for its first, most abundant spring bloom on the wood produced during the current season. Cutting the plant back aggressively during late summer, fall, or winter will inadvertently remove these newly formed flower buds. The consequence of a late cut is a significant reduction of the spring flowers. The only acceptable form of pruning outside of the spring and early summer window is the removal of dead, diseased, or broken wood. This maintenance can be performed at any time of year for the health of the plant, rather than for shaping or bloom production.