When is the best time of year to prune or trim my lilac bushes?
The Gardener’s Answer
Hello, Paula: Lilacs (Syringa) are a wonderful treat for our senses. Each spring, healthy plants provide us with a bounty of fragrant flowers. Annual maintenance will help lilac shrubs in terms of vigor as well as overall appearance. Spring-flowering shrubs such as lilacs should be pruned immediately after they have finished blooming. Pruning too early will remove potential flowers, and pruning too late can make them more susceptible to winter injury. So, after you have enjoyed this season’s blooms, you can get out your pruning tools. Lilacs will benefit from being thinned, which means removing some of the older, woodier branches. This is especially true for the center of the plant where if it has not been thinned recently can become dense and does not allow for good air circulation or filtered sunlight. Both can lead to disease problems. If your lilacs are old and need to be rejuvenated, you can remove one-third of the old wood at this time of the year (late winter/early spring). Take the branches back all the way to the ground. Continue this over the next three years and your plants will be much happier. As always, make sure your pruning tools are clean and sharp. If you want more detailed information on pruning your lilacs, visit http://ces.ca.uky.edu/floyd-files/HO59.pdf