How to Trim a Lilac

If your lilac is less than wonderful, it might be time for a trim. Before you get to work, make sure you know how to trim a lilac. It's not hard, but there are a few things to know before you set blade to limb. To ensure success you must know when and why as well as how to trim a lilac.

Is your lilac just perfect and you want to keep it that way?

Remove spent flowers as they happen. This allows the tree's energy to be focused on growth and future bud development rather than growing seeds. After all the flowers are finished, it is time to trim. Remove all 'suckers' from around the base. Trim enough branches to allow the bush to be airy and all the leaves to get light. Also cut away dead branches and any branches that are rubbing on other branches. If you delay in trimming until later in the season, you will not harm the lilac, but you will be cutting away next season's flowers.

Is your lilac out of control and you want to know how to cut it down to size?

An overgrown lilac can be trimmed in one of two ways.

The extreme way is to simply whack everything down to a height of 6 to 8 inches. This technique should be applied in late winter. New shoots will come up during the growing season. The following late winter, choose several of the healthiest shoots to become your new lilac. Cut everything else off at ground level. The chosen shoots should be cut back to just above a bud to encourage branch growth. Your new lilac will not bloom for at least 3 years.

If you'd like to get the lilac under control but you don't wish to start quite so drastically, the common practice is to cut 1/3 of the bush's old growth each year. By the third year, when you are trimming off the last third of the original bush, the growth that happened after the first trim will be ready to bloom. The most reasonable way to accomplish this is to cut one third of the branches from all areas of the lilac, rather than taking a section off. This is a task best done just after all the flowers have finished.

Has your lilac been neglected for so long that it now flowers only at the top, 15 feet above your head where you can't enjoy them?

In this scenario, it is best to follow the instructions above for cutting 1/3 per year.

Trimming your lilac will ensure that it gives you pleasure for many years. An untended lilac is pretty much 'finished' after 20 years, but a tended one can last much longer. Now that you know how to trim a lilac, you can see that it's not difficult or complex.