How to Prune Syringa

Syringa is a hardy shrub that's commonly referred to as lilac. Lilacs produce highly-fragrant blooms in early spring that last a mere week or two, depending on the species and weather conditions. If followed by a dry spell, blooming may be prolonged. Wet weather will shorten the blooming season, causing the blooms to turn a rusty brown color. Keeping syringa in shape may require selective pruning on a yearly basis.

Things You'll Need

• Pruning shears
• Handsaw

Instructions

1. Prune syringa in the spring, soon after it has ceased blooming. Lilacs set buds for the following season early in the summer. Even though you may not be able to see the buds, pruning lilacs in the summer may destroy next year's blooms.

2. Remove all dead or dying wood from the interior of the bush with a set of sharp pruning shears. Use a small handsaw to remove larger branches. Cut the dead wood all the way back to the main branch.

3. Trim away branches that are twisted, or cross the center of the bush. Opening the center of the bush increases air circulation and reduces the chance of disease.

4. Selectively remove 1/3 of the old wood by cutting it back to ground level. Cut any suckers, or young shoots, from around the base of the bush. If desired, transplant these shoots to a new location with similar growing conditions.

5. Trim the tops of the branches to maintain the overall shape of the bush. The canopy should be rounded. Avoid hacking the top of the bush in a flat cut.

6. Remove spent blooms by pruning the branches. This encourages the onset of new blooms the following year. Often, two blooms will grow to replace the one you removed, creating a gorgeous display the following year.

Tips & Warnings

• Cutting back 1/3 of the old wood each year allows new growth to flourish, and will completely rejuvenate an old bush.

References

• Botany.com
• North Carolina State University: Pruning Lilacs
• The Gardener's Network: How to Prune Lilacs