How to Get Rid of Lilac Shoots and Suckers

Lilac suckers are vigorous shoots that sprout from the root system, often popping up several feet from the main trunk, and the only reliable way to get rid of them is to remove them at or below ground level repeatedly until the plant’s energy reserves for suckering are depleted. A single session of cutting won’t solve the problem because lilacs, especially common lilac (Syringa vulgaris), are among the most persistent suckering shrubs in temperate landscapes. The good news is that a combination of proper pruning technique, root management, and a bit of patience will bring even an aggressive colony under control.

Why Lilacs Sucker So Aggressively

Lilacs spread by sending lateral roots outward from the base of the plant. Buds along these roots can break dormancy and push new stems up through the soil, sometimes emerging a surprising distance from the parent shrub. This is a survival strategy: if the main trunk is damaged by weather, browsing, or disease, the root system already has backup shoots ready to take over. From the plant’s perspective, suckering is a feature. From yours, it can turn a single ornamental shrub into a thicket that swallows a fence line or crowds a walkway.

Several things encourage heavier suckering. Aggressive pruning of the main canopy, root disturbance from nearby digging, drought stress, and damage to surface roots from lawn mowers or string trimmers all signal the root system to push out more shoots. Grafted lilacs present their own wrinkle, which we’ll get to below. But the underlying biology is simple: any time the plant senses that top growth has been lost or threatened, it compensates by sending up more shoots from below.

The Right Way to Remove Suckers by Hand

Pruning is the first line of defense, and how you prune matters more than most gardening guides let on. The instinct is to grab a pair of loppers and clip the sucker at ground level. That works in the short term, but cutting a sucker cleanly at the soil surface leaves the dormant buds at the base of that shoot intact. Within weeks, two or three new shoots can emerge from the same spot.

A more effective approach is to trace each sucker down to where it connects to the lateral root. Push soil aside, follow the stem underground, and pull or cut it flush with the parent root. If you can rip the sucker off with a sharp tug, even better, because tearing it away tends to remove more of the basal bud tissue than a clean cut does. This is messy, hands-in-the-dirt work, but it dramatically slows regrowth compared to surface-level snipping.

Timing helps, too. Removing suckers in late spring or early summer, once the new shoots have leafed out and spent some of the root’s stored energy but before they harden off and start photosynthesizing efficiently, hits the plant at its most vulnerable moment. You’re forcing it to spend resources regrowing shoots that never pay those resources back. Repeating this for two or three seasons in a row progressively weakens the suckering response.

Keeping Your Tools Clean

Lilacs are susceptible to bacterial blight caused by Pseudomonas syringae, a pathogen that spreads from plant to plant through contaminated tools, wind, rain, and insect activity.¹ When you’re cutting suckers from multiple plants or moving between a diseased lilac and a healthy one, wiping pruner blades with rubbing alcohol or a dilute bleach solution between cuts is a simple precaution. Bacterial blight causes browning and dieback of shoots and can become severe enough to disfigure the whole shrub. The last thing you want is to spread disease while trying to tidy up unwanted growth.

Root Barriers and Root Pruning

If your lilac sits next to a lawn, a garden bed, or a walkway where suckers are especially unwelcome, physical root barriers can intercept the lateral roots before they send shoots into contested territory. A strip of heavy-duty landscape edging or a sheet of rigid plastic buried vertically 12 to 18 inches deep around the perimeter of the planting area blocks roots from spreading outward. The barrier doesn’t eliminate suckering entirely; it just confines it to the area immediately around the main plant, where you can manage it more easily.

Root pruning is the more aggressive cousin of this approach. Using a sharp spade or a root-pruning saw, you cut through the lateral roots in a circle around the trunk at whatever radius you want to maintain as the plant’s footprint. This severs the connection between the parent root system and any suckers beyond the cut line. Those orphaned suckers will die on their own once separated from the root network. The trade-off is that root pruning can stress the plant and, ironically, stimulate a burst of new suckers inside the pruned zone as the root system tries to compensate. You may need to repeat root pruning annually for a couple of years before the plant settles down.

Chemical Options for Sucker Suppression

Gardeners sometimes ask whether a herbicide or growth regulator can kill the suckers without harming the parent lilac. The honest answer is that chemical control of suckers on ornamental shrubs is limited and imperfect.

Non-selective herbicides like glyphosate will kill a sucker if you paint it on the cut surface or carefully apply it to the foliage of the unwanted shoot. The risk is that because the sucker shares a root system with the parent plant, the chemical can translocate back to the main shrub and cause damage. If you choose this route, the safest method is to cut the sucker, let a small amount of regrowth appear, and then brush concentrated glyphosate onto the fresh leaves of just that regrowth with a foam paintbrush. This minimizes the volume of chemical entering the shared root system. Even so, there is no guarantee the parent plant won’t show some stress.

Growth regulators offer a different angle. Research on hazelnut trees, another woody species with aggressive suckering, has shown that 1-naphthaleneacetic acid (NAA) applied as a basal spray delayed sucker regrowth by roughly one to three times compared with untreated trees, and sequential applications significantly reduced both sucker height and fresh weight.² NAA is sold commercially as a sucker suppressant under various brand names and is labeled for use on some ornamental and fruit trees. Whether it is labeled for lilacs specifically depends on the product and your region, so reading the label is essential. The hazelnut research also found that suppressing suckers with NAA actually increased trunk growth and canopy volume at some sites, suggesting the plant redirects energy into the main stem when suckering is suppressed.² That’s an encouraging finding for anyone trying to strengthen a lilac’s main framework while discouraging unwanted shoots.

Selective herbicides like triclopyr, sold for brush control, are sometimes recommended online for painting onto sucker stumps. These carry the same translocation risk as glyphosate and can be even more damaging to broadleaf plants. The safest chemical approach is usually to combine mechanical removal with a growth regulator rather than reaching for a broadleaf herbicide.

Grafted Lilacs and the Rootstock Problem

Many named lilac cultivars, particularly French hybrids and the elegant Japanese tree lilac, are grafted onto the rootstock of common lilac or, in some cases, privet. When a grafted lilac sends up suckers, those suckers are genetically the rootstock species, not the cultivar you bought. If left unchecked, rootstock suckers can outcompete the grafted top and eventually take over the plant. You’ll notice the difference because rootstock suckers often have different leaf shape, smaller or differently colored flowers, or in the case of privet rootstock, an entirely different growth habit.

For grafted lilacs, removing suckers is not optional maintenance but a matter of preserving the plant you paid for. The graft union is usually visible as a slightly swollen or angled area a few inches above the soil line. Everything emerging below that union is rootstock and should be removed as soon as it appears. If you want to avoid the grafting headache entirely, look for lilacs sold as “own-root” plants. These are propagated from cuttings or tissue culture rather than grafted, so every sucker that appears is genetically identical to the main plant. Own-root lilacs still sucker, but at least the suckers produce the same flowers.

When You Want to Remove a Lilac Colony Entirely

Sometimes the goal isn’t managing suckers but eliminating the entire lilac planting. This is a bigger project than most people expect. Cutting the main trunk to the ground triggers a massive suckering response, and the root system of an established lilac can survive for years, sending up new shoots each spring. Stump grinding helps but doesn’t reach the lateral roots, so suckers continue to appear across the former footprint of the plant.

The most thorough approach combines cutting the main stems, immediately treating the fresh-cut stumps with a concentrated glyphosate or triclopyr product, and then monitoring the area over the next two growing seasons to spot and treat any regrowth. Each new shoot that appears can be sprayed or wiped with herbicide individually. Because these orphaned suckers are small and have limited leaf area, they are more vulnerable to herbicide than the original plant was. Persistence matters more than potency here; a single treatment almost never finishes the job.

For gardeners who prefer to avoid chemicals entirely, repeated cutting throughout the growing season, sometimes called “starving the roots,” works but takes longer. Every time a new shoot appears and you cut it before it has a chance to photosynthesize for more than a week or two, you drain a little more stored energy from the root system. Over two to four seasons of diligent cutting, the roots eventually exhaust their reserves and stop sending up new growth. Covering the area with a heavy opaque tarp or several layers of cardboard topped with mulch can accelerate this process by blocking light from any emerging shoots.

Mulching and Cultural Practices That Help

A thick layer of organic mulch, three to four inches of wood chips or shredded bark, around the base of a lilac does two useful things. First, it keeps surface roots cooler and moister, which reduces the kind of stress that triggers heavy suckering. Second, it creates a physical barrier that slows down emerging suckers, making them easier to spot when they’re still small and soft. Suckers that have to push through several inches of mulch emerge later and weaker than those growing through bare soil.

Avoid cultivating or tilling the soil around lilacs. Running a rototiller through a lilac’s root zone is essentially slicing every lateral root into pieces, and each piece with a viable bud can regenerate into a new shoot. Even routine garden work like edging a bed with a flat spade near lilac roots can stimulate a flush of new suckers. If you need to plant annuals or perennials near a lilac, dig individual holes carefully rather than turning over the entire bed.

Watering and feeding the plant adequately, without overdoing nitrogen, also helps. A well-nourished lilac that isn’t drought-stressed has less biological incentive to throw energy into vegetative reproduction. Heavy nitrogen fertilization, on the other hand, promotes leafy growth of all kinds, including suckers, so balanced fertilizers or compost are a better choice than lawn-type high-nitrogen products.

Using Suckers for Propagation

If your lilac is growing on its own roots, the suckers it produces are free plants. Each one is a genetic clone of the parent, complete with the same flower color and fragrance. Dig around the base of a healthy sucker in early spring or late fall, follow it back to the connecting root, and sever it with a clean cut. Lift the sucker with as much of its own root mass as you can, pot it up or transplant it directly, and keep it watered for the first season while it establishes an independent root system.

Suckers from grafted lilacs are a different story. Because they’re growing from rootstock, transplanting them gives you a common lilac or privet rather than the named cultivar. That may or may not be what you want. Common lilac rootstock suckers will eventually bloom, typically with the familiar pale purple flowers and strong fragrance, which some gardeners are perfectly happy with. Just don’t expect the double blooms of ‘Charles Joly’ or the pure white of ‘Mme. Lemoine’ if those were what you originally planted.

Realistic Expectations and Common Mistakes

The biggest mistake gardeners make with lilac suckers is treating it as a one-time chore. Suckering is baked into the biology of most lilac species, and managing it is an ongoing part of owning the plant. Expecting to eliminate suckers permanently from a healthy, vigorous lilac is like expecting a lawn to stop growing. You can reduce the frequency and severity, but you can’t override the plant’s genetics.

The second most common mistake is mowing over suckers in the lawn and assuming that handles the problem. A lawn mower clips the shoot at two or three inches, leaving the basal buds completely intact. The sucker just regrows, often branching into multiple stems from the cut point. You end up with a denser patch of suckers than you started with. If suckers are coming up through lawn grass, it’s worth the few minutes to dig each one out individually rather than running the mower over them week after week.

Finally, many gardeners underestimate how far from the trunk suckers can appear. Lilac roots commonly extend well beyond the drip line of the canopy. Suckers popping up six, eight, or even ten feet from the trunk are normal for an established plant. If mysterious shoots are appearing in a flower bed or along a fence and you can’t identify the source, trace the stem below ground. You may find it leads back to a lilac you didn’t suspect.