As much as we all love those gorgeous, fragrant lilac blooms, these plants can definitely have a mind of their own. If your lilac starts spreading like wildfire via root suckers, it can quickly go from a garden favorite to a major headache. Keeping a wild lilac in check isn’t always easy, but don’t worry—I’ve got some tips to help you rein in those wandering roots.
Just how aggressive are lilac roots?
Lilacs have an incredible will to live, and it all starts with their vigorous root systems. Even if a lilac looks completely dried up and you cut it down to the stump, it can still make a comeback. As long as those roots are healthy, the plant will keep pushing out new growth. Plus, because they have wide-spreading roots that send out runners (suckers), you might suddenly find a new lilac popping up in a completely different part of your yard!
If you want to stop your lilac from taking over the garden—and prevent its dense root network from hogging all the water and nutrients from your other plants—you need to take action. The goal is to limit the root growth to one specific spot. Just be careful not to make the area *too* small, or you’ll starve the plant of what it needs to thrive.
Install a root barrier for your lilac
The most effective way to handle this is by installing a root barrier around the plant. You can pick these up at your local garden center or order them online. They’re usually made of a tough, flexible material that you can cut to the size you need.
How to install the barrier:
- Dig a trench in a circle about 5 to 6 feet away from the main trunk.
- Insert the root barrier at least 24 inches (60 cm) deep.
- Backfill the trench with soil.
There are two key things to keep in mind here. First, make sure you give the lilac plenty of breathing room—a radius of about 5 or 6 feet is ideal for healthy growth. Second, don’t skimp on the depth! You need that barrier to go down at least 60 centimeters to prevent the roots from simply diving under it and tunneling their way to freedom elsewhere in your lawn.
