Rejuvenate leggy lilacs
My 30-year-old lilac has grown leggy and unattractive. How can I prune this bush to improve its appearance?
Donna Hartmuss, Norwalk, CT
Remove older canes and spent flowers to renew leggy lilac bushes.
Photo/Illustration: Christine Erikson
Erica Glasener, a contributing editor to Fine Gardening, replies: If the plant has become unruly and misshapen, some renovation by pruning is in order. First, cut out one-third of the oldest canes at ground level. This will encourage some younger shoots to fill in. Cut back the remaining stems to about half of their original size. Also, remove the spent flowers once they’ve bloomed, and prune back to the first two side branches below where the flowers appeared. This way the plant is putting its energy into growth rather than setting seed.
Fertilize with a generic mix of 10-10-10 in early spring, and keep the plant watered, especially during dry spells in the hot summer months. A hard pruning may delay reflowering, so you may want to stagger the steps over a two- to three-year period.
From Fine Gardening 58, pp. 12