Growing and Caring for Lilacs

By Ava Green

Is there anything sweeter than the scent of Lilacs in the spring? These beloved shrubs are remarkably easy to grow and will reward you with weeks of fragrant blooms for little or no effort. But a bit of attention can make a big difference, especially if you’ve noticed your blooms getting smaller or fewer with each passing year. 

To help your lilac put on its best show, keep these steps in mind:

• Plant in full sun, at least 6 hours of direct sunlight a day, in well-draining soil
• Water newer plants during prolonged periods of drought until established (the first 3 years)
• Feed your lilacs annually with a balanced fertilizer (10-10-10, for example)
• Follow spacing instructions and prune yearly. Pruning is a very important step, and it’s well worth it.

Knowing When to Prune is Key

Timing is everything when it comes to pruning your lilacs. After the blooms fade, you have a two-week window to prune before the shrub sets its buds for next year's flowers. Yes, they set buds this year that will bloom next year! Pruning lilacs in the fall or the early spring risks cutting off all of the flower buds for the following year. Mark your calendar and prune promptly after flowering.

It also helps to understand how lilacs grow: Younger, thinner lilac stems produce more flowers. Older, thicker stems are more prone to disease and pests. Keeping this in mind will help with pruning decisions.

How To Prune Young Lilacs

If your lilac has been in the ground for less than three years, leave it alone; it doesn’t need pruning yet. Many young lilacs won’t bloom during those first few years.

After three years, once your shrub is established, begin by removing just one of the thickest, oldest stems down to the ground every 2 years. This gentle approach prevents the shrub from becoming overgrown while encouraging newer, flower-producing growth. 

How To Prune Older, Overgrown Lilacs

If your lilac has been neglected or grown out of control, you have two options:

Option 1: Gradual Rejuvenation

Begin by removing any damaged stems, as these invite pests that can harm the entire shrub. Next, remove only the largest, oldest stems by cutting them right down to the ground. The key is to remove no more than one-third of the living wood (dead stems don’t count toward that total). Leave the younger, thinner stems intact so your shrub can still bloom the following year. Repeat this process each spring for three years, and you’ll gradually restore the shrub to its full, flowering potential without sacrificing a single bloom season.

Option 2: Full Cutback

For a severely overgrown lilac that has been largely ignored, a complete cutback is often the most practical solution. Cut the entire shrub as close to the ground as possible, either in early spring or immediately after blooming. Yes, this breaks the general rule of never removing more than one-third of live wood, but lilacs are remarkably resilient and respond well to this kind of hard reset. By the end of summer, you will have healthy new stems of three to five feet tall. While the shrub won’t bloom for approximately three years after a full cutback, the long-term results are well worth the wait.

Deadheading Your Lilacs

Deadheading, or removing spent flower clusters after the blooms fade, is a simple task that’s separate from pruning, and can be done during that same two-week post-bloom window. When you trim off faded blooms, the plant redirects its energy from seed production toward building bigger, healthier buds for the next year. It takes only minutes and can make a meaningful difference in the size and abundance of next year’s flowers. 

A Note on Lawns and Lilacs

If your lilac grows near a lawn, be mindful of how much fertilizer you’re applying to the surrounding grass. Lawn fertilizers are typically high in nitrogen, which encourages lush leaf growth, but too much nitrogen reaching your lilac’s roots will suppress flower production.

Worthy Rewards

Lilacs are remarkably long-lived, often outlasting the gardens and even the homes they were planted beside. So whether you’re nursing a young shrub through its first few years or breathing new life into an old, overgrown beauty, the effort you put in now is an investment that will keep rewarding you, and perhaps generations after you. Every single spring!