Photo/Illustration: Jennifer Benner
One of the few plants that survived my garden renovation was an old, overgrown lilac. I saved it because it blocked the view of my neighbor’s garage and, more important, it had steel-blue double blossoms. These flowers were as beautiful as they were fragrant, but they were so few and so high up on the shrub that it was difficult to enjoy them. Since lilacs can handle severe pruning, I knew there was no need to give up on this long-neglected plant, and I went ahead with a rejuvenation pruning.
The common French lilacs (Syringa vulgaris cvs.) produce the most and the largest flowers on stems that are not more than 5 or 6 years old. As the stems get older, the flowers become fewer, smaller, and more out of reach. But with proper pruning, a lilac can produce flowers reliably for decades. What technique you use depends on the age of your shrub. An annual maintenance routine keeps plants vigorous. For those lilacs that have seen better days, like mine, a more severe pruning may be in order.