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You can stop lily of the valley from spreading by using physical barriers, regular division, and consistent removal of its rhizomes.
If you’ve planted this fragrant ground cover and now it’s taking over your garden, you’re not alone.
Lily of the valley spreads aggressively through underground stems called rhizomes, and it can quickly become a stubborn invader.
The good news is that stopping lily of the valley from spreading is totally doable if you use the right strategies.
In this post, we’ll walk you through practical ways to control lily of the valley, from simple hand-pulling to smart landscaping tricks.
Let’s dig in and get that beautiful but bossy plant back in its lane.
Why Lily of the Valley Spreads So Quickly
Understanding how lily of the valley spreads is the first step to stopping it.
Lily of the valley spreads both by seeds and, more famously, by those fast-moving rhizomes.
These underground stems can travel several feet in a single season, sending up new shoots as they go.
So when you ask how to stop lily of the valley from spreading, you’re really asking how to outsmart its root system.
Once you know what you’re dealing with, you can choose the right method to keep this plant contained.
1. The Rhizome Network Is the Real Enemy
Most people think the leaves are the problem, but the real culprit is below the soil.
Lily of the valley spreads through a dense mat of rhizomes that store energy and send out new growth constantly.
If you just pull up the leaves, you’ll miss the rhizomes, and the plant will bounce right back.
To stop lily of the valley from spreading, you have to target those underground stems directly.
Digging them up is the most reliable way, but you have to be thorough.
2. Seeds Add Another Layer of Spread
While rhizomes do the heavy lifting, lily of the valley also spreads by seeds.
After the white bell-shaped flowers fade, they form small red berries that birds love.
Those birds then drop seeds far from your garden, creating new patches.
So stopping lily of the valley from spreading means you also need to remove those berries before they ripen.
Deadheading the spent flowers is a simple habit that prevents seed spread.
Effective Ways to Stop Lily of the Valley from Spreading
If you’re ready to take action, there are several proven methods to stop lily of the valley from spreading.
Each one works best depending on your garden setup and how much time you have.
Let’s break down the most effective techniques you can start using today.
1. Digging Up the Rhizomes Thoroughly
The most direct approach to stop lily of the valley from spreading is physical removal.
Use a garden fork to loosen the soil around the entire patch, then gently lift the rhizomes out.
It’s crucial to get every piece, as even a small fragment can regrow.
The best time to do this is in early spring or fall when the soil is moist and the roots are easy to pull.
Be prepared to repeat this process every few weeks until the patch is fully exhausted.
2. Installing a Physical Barrier
If you want a long-term solution, a physical barrier is a great way to stop lily of the valley from spreading.
Dig a trench around the area and sink a sturdy barrier like metal edging or thick plastic sheeting.
The barrier should go at least 12 inches deep to prevent rhizomes from sneaking underneath.
This method works well if you want to keep lily of the valley in a specific bed without killing it.
Just check the barrier yearly to make sure the rhizomes haven’t found a way over or under it.
3. Smothering the Patch with Mulch or Cardboard
Smothering is a more hands-off way to stop lily of the valley from spreading.
Lay down a thick layer of cardboard or landscape fabric over the entire patch, then cover it with mulch.
This blocks sunlight and prevents new shoots from emerging.
You’ll need to keep the smothering material in place for at least a full growing season.
While this method is effective, it also kills anything else in that area, so plan accordingly.
4. Using Herbicides as a Last Resort
For large infestations, carefully applied herbicides can help stop lily of the valley from spreading.
Look for a systemic herbicide containing glyphosate, which travels down to the roots and kills the rhizomes.
Apply it on a dry, calm day directly to the leaves, avoiding any nearby desirable plants.
You might need several applications to fully eradicate the patch.
Always follow the label instructions and remember that selective herbicides won’t work on this plant.
5. Regular Division Keeps It in Check
If you actually enjoy lily of the valley but just want to stop lily of the valley from spreading too far, try regular division.
Every two to three years, dig up the entire clump and split it into smaller sections.
This keeps the plant vigorous while preventing it from running wild.
Replant the divisions only in controlled areas, and give away or compost the extras.
It’s a win-win because you get more plants without the takeover.
Preventing Lily of the Valley from Spreading in the Future
Once you’ve tackled the current spread, the next step is prevention.
Stopping lily of the valley from spreading in the future takes a bit of maintenance, but it’s not hard.
Incorporate these habits into your garden routine to keep things under control.
1. Choose a Contained Location
Where you plant lily of the valley matters a lot for stopping lily of the valley from spreading.
Avoid open garden beds and instead plant it in a raised planter or a spot bordered by concrete.
This naturally limits where the rhizomes can go.
If planting in the ground, use the barrier method from above right from the start.
A little upfront planning saves you tons of digging later.
2. Monitor and Remove New Growth Early
Catching new shoots early is a simple yet powerful way to stop lily of the valley from spreading.
Take a quick walk around the perimeter of your patch every week during the growing season.
If you spot any shoots outside the designated area, pull them up immediately with the rhizome attached.
Consistent monitoring makes a huge difference and prevents the problem from escalating.
This is the easiest habit to adopt and the most effective in the long run.
3. Dispose of Removed Plant Material Properly
If you want to fully stop lily of the valley from spreading, you have to dispose of the pulled plants correctly.
Never toss rhizomes or berries into your compost pile, as they can survive and regrow.
Instead, bag them up and send them to the landfill.
You can also dry them out in the sun on a tarp for a few days before composting, but bagging is safer.
This prevents accidental re-spreading through your own gardening habits.
So, How Do You Stop Lily of the Valley from Spreading?
You can stop lily of the valley from spreading by combining physical removal, barriers, and consistent monitoring.
There’s no single magic fix, but with a little persistence, you can absolutely control this determined plant.
Start by digging up the rhizomes thoroughly, then install a deep barrier if you want to keep it.
Smothering works for areas where you want total removal, and herbicides are a last resort for large patches.
Finally, keep an eye out for new growth and remove those red berries before they seed.
With these strategies, you’ll stop lily of the valley from spreading and enjoy a garden that’s truly yours.