Rejuvenate an Old Lilac

May 18, 2008Updated 7 months ago

Spring just wouldn’t be complete without the scent of the lovely lilac wafting in the breeze. The beautiful lavender cascades falling from green leaved bushes thrill the soul and make one want to bury one's face in the blooms.

But, what if the lilac bush in your backyard has been neglected and no longer produces lush blooms that fill the air with perfume. You didn’t know you had to prune it or maybe you pruned it at the wrong time. Maybe you just moved in and were thrilled at the prospect of collecting branches of lilacs to fill your home with fragrant flowers. The bush was just so old and unkempt that it didn’t produce anything but a bunch of dark green leaves. Calm down! There is still hope!

A neglected lilac will become very overgrown and woody. Cutting the plant back forces it to produce fresh, young growth. Cut the overgrowth back in late winter or very early spring when the weather is still cold and the plant is dormant. This absolutely will sacrifice the current year’s blooms but it does give the plant a whole season to recover.

When pruning an overgrown lilac, remove the dead stems first. The best thing to do this with is a narrow-bladed pruning saw since the narrow blade will fit between the closely spaced stems. Cut out all the dead stems from the cluster of stems and discard them.

Go to the bottom of the shrub and remove the small suckers that are coming up from the ground or around the base of the bush. Then, stand back and look at the shape of the tree. Cut unwanted branches from the bottom of the shrub. Cut back tall branches to about 18 to 24 inches above the ground. Shape with pruning shears to the desired shape.

During the growing season apply a slow-release fertilizer and mulch a few feet wide around the stems. Water weekly during the summer and fall to soak the roots if there is no rain.

Trim the new growth back in the winter, when the shrub is dormant. Remove any new shoots that grow toward the inside of the shrub as they will make the plant too dense. When pruning stay close to the main branch. Don’t cut back all the suckers at the bottom this time.

The next year you may not have many blooms, if any, but the third year the lilac will be back to good health. Keep it in shape by removing the spent blossoms so the plants energy will go into growth rather than into making seeds.

If you don’t want to cut back your lilac all at once, you can do this over a three-year period. During late winter remove 1/3rd of the largest and oldest stems. In each of the following two winters, remove another 1/3rd of old stems and thin new shoots. You will have a few flowers every spring this way.

With a little loving care and know how you can rejuvenate a spent lilac bush so that it will once again produce heavenly scented blossoms.