How to Control Lilac Sucker Growth (2025)

Lilacs are known for what is called “sucker growth,” which is when the plant sprouts from the root system. Some varieties are more prone to sucker growth than others. Unfortunately, they’re hard to control because the more you damage the roots by digging or cutting the suckers, the more the plant produces — it’s a stress response.

Still, the best ways to control lilac suckers are using root barriers, growth inhibitors, careful pruning, and selective herbicide application. Read on to learn what methods you can try to stop your lilac suckers from popping up.

Top Methods to Control Lilac Suckers

Controlling lilac suckers requires a combination of methods — installing deep root barriers around the plant can help contain growth. Regular pruning, especially by tearing suckers rather than cutting, can discourage regrowth.

Apply growth inhibitors like Monterey Sucker Stopper for chemical control. In extreme cases, careful use of herbicides on isolated suckers may be necessary — persistence is key in managing sucker growth.

Here are the best methods to stop lilac suckers:

Use a plastic barrier landscape cloth. Weed control fabric works mainly by blocking sunlight and seed germination — it doesn’t stop shoots and roots from penetrating the fabric. A plastic barrier with mulch should prevent all new growth, but it also blocks water and nutrients and holds in heat — you’ll need to keep an eye on any plants surrounded by such a barrier to make sure they aren’t cooking.

Monterey Sucker Stopper is a commercial product containing the growth inhibitor NAA (naphthalene acetate), designed to stop the growth of suckers from roots and pruning wounds. It is widely used in the orchard industry but is available for home gardens in a ready-to-use spray bottle.

Remove suckers by tearing, not cutting. You want to remove the sucker all the way back to the root where it originates, and tearing them off will help remove dormant buds at the base.

Dig them up with a sharp spade, removing the root as well. These can be transplanted if you wish.

Prune the roots in a circle, using deep plunges of a sharp shovel or pruning shears, and then treat the suckers outside the circle with an herbicide such as Roundup®. Avoid spraying herbicide on any suckers still connected to the parent plant.

You might also try surrounding your plant with a 6–12” deep underground barrier, such as buried metal or plastic landscape edging, to try to contain the roots. If your lilac is well established, its roots will likely go deeper than this, but it can help.

With root pruning or underground barriers, make the circle at least 2-3 feet wide, and ideally as wide as the shrub’s drip line.

Obviously, most of these tips will have to be repeated as the plant continues to sprout. I still have suckers coming up from a lilac I dug up and removed ten years ago — it’s not a battle easily won. Some gardeners deal with the problem by clearing more space around the shrub and just letting it spread, or by removing the shrub completely and having the roots ground out.

Why Lilac Suckers Grow

Lilac suckers are a natural growth response of the plant. They occur when the root system produces new shoots, often as a stress response to damage or as part of the plant’s spreading or rejuvenation mechanisms. Some lilac varieties are more prone to suckering than others.

Can You Replant Lilac Suckers?

You can replant lilac suckers to create new bushes. Carefully dig up suckers with roots attached in early spring or fall. Plant them immediately in a prepared transplanting location with well-draining soil. Keep the new plants well-watered until established. This can be a cost-effective way to propagate lilacs but remember that the new plants will have the same suckering tendency as the parent.

Alternative Plants to Lilacs

If lilac suckers are too problematic for you, consider alternatives like butterfly bush, mock orange, or viburnum. These plants offer similar aesthetic appeal with fewer sucker issues. Dwarf lilac varieties or non-suckering cultivars like ‘Miss Kim’ can also be good options. Always research plant characteristics before picking one to make sure it suits your gardening needs.

Final Thoughts

Controlling lilac sucker growth requires patience and a multi-faceted approach. From my years of experience, I’ve found that combining methods like root barriers, proper pruning techniques, and selective use of growth inhibitors gives you the best results.

While it may seem like an ongoing battle, with consistent effort, you can manage lilac shoots effectively and enjoy the beauty of your lilac trees and bushes without the constant spread of unwanted shoots. Remember, each garden is unique, so don’t hesitate to experiment with different control methods to find what works best for your lilac bushes.