Getting Rid of Lily of the Valley: A Comprehensive Guide

Lily of the valley is a popular garden plant that is loved for its sweetly fragrant, nodding white bell-shaped flowers that bloom in spring. However, this spreading perennial can quickly become invasive and take over your garden beds.

In this comprehensive guide, we’ll cover everything you need to know about getting rid of lily of the valley, from identification and behavior to organic and chemical control methods.

What is Lily of the Valley?

Lily of the valley (Convallaria majalis) is an herbaceous perennial plant that is native to Asia and Europe. It grows from rhizomes underground that spread aggressively, forming thick mats. The arching stems grow 4 to 12 inches tall and produce pairs of oval, dark green leaves along their length.

Delicate white bell-shaped flowers dangle from the stems in spring, exuding a lovely sweet fragrance Small red-orange berries may follow the flowers, which can allow the plant to spread readily by seed as well as by rhizomes.

Is Lily of the Valley Invasive?

While lily of the valley is valued for its showy spring blooms and fragrance, it can definitely turn into a thug in the garden. Both its rapidly spreading rhizomatous roots and its prolific seeds enable it to colonize areas quickly.

For this reason, many sources advise against planting lily of the valley, as it can be difficult to eradicate once established. The Missouri Botanical Garden identifies it as an invasive plant that should not be used in home gardens in the Midwest. It has also been labeled invasive in other regions like Alaska, Wisconsin, the Pacific Northwest, Northeast, and Southeast.

How Does Lily of the Valley Spread?

Lily of the valley spreads readily both through rhizome growth underground as well as seed dispersal. Here’s a closer look at both mechanisms:

Rhizome Spread: The underground rhizomes grow horizontally at a rapid pace, expanding the plant’s footprint and allowing it to pop up through the ground in new locations. The rhizomes penetrate deeply and extensively.

Seed Dispersal: Each flower stalk can produce several berries. Birds and other wildlife eat the berries and then disperse the seeds through their droppings into new areas, enabling the plant to spread. The seeds can also be dispersed by water.

Is Lily of the Valley Hard to Get Rid Of?

The fact that lily of the valley spreads vigorously by underground rhizomes and above-ground seeds makes it very hard to get rid of once established.

Trying to dig it out usually leaves behind rhizome pieces in the soil, which can lead to the plant popping back up. The seeds can build up a seed bank in the soil, causing new plants to continuously germinate once the established plants are removed.

For these reasons, eradicating lily of the valley takes persistence and dedication. You’ll likely need to use a combination of manual removal and chemical treatments to fully get rid of it.

Dangers of Lily of the Valley

While lily of the valley is a beautiful garden plant, it does come with some cautions. Here are a few things to know about its dangers:

• All parts of the plant, including the flowers, are poisonous if ingested. They contain cardiac glycosides that can cause vomiting, diarrhea, and abnormal heart function.

• Keep pets and children away from lily of the valley, as ingestion can be fatal in rare cases. Avoid planting it if young kids or pets frequent your yard.

• The plant can become invasive and crowd out desirable plants in your garden. It’s illegal to sell, propagate, or plant lily of the valley in some regions because of its invasive tendencies.

• Skin contact with the plant can cause skin irritation in some people. Wear gloves when handling lily of the valley.

How to Get Rid of Lily of the Valley Organically

If you want to get rid of lily of the valley without resorting to chemical herbicides, here are some organic approaches you can try:

Manual Removal

Digging up lily of the valley is effective but extremely labor-intensive due to its extensive root system. Here are some tips:

• Use a garden fork or shovel to dig down at least 10-12 inches to get underneath the rhizomes.

• Remove every piece of root and rhizome you find, as any left behind can re-sprout.

• Dispose of the plant material in trash bags, not in compost piles.

• Be persistent and keep digging when you see new growth. Multiple digs may be needed over time.

Smothering

Smothering lily of the valley by cutting off light and air to the plant can kill it over time.

• Mow or weed whack the area to ground level in early spring.

• Cover the area thoroughly with cardboard, landscape fabric, wooden boards, or 4-6 layers of newspaper.

• Top with 3-4 inches of mulch or soil.

• Leave covered for at least one full growing season before removing the barrier and planting something new.

Solarization

Solarizing the soil uses the sun’s heat to kill plants and seeds.

• Mow down and remove existing growth in spring.

• Wet the area thoroughly.

• Cover with clear plastic sheeting, sealing the edges with soil or bricks.

• Leave the plastic in place for at least 6-8 weeks through the hottest part of summer.

• Remove the plastic in fall and replant with desirable plants.

Vinegar

Plain horticultural vinegar containing 20% acetic acid can kill lily of the valley when applied directly to its leaves and stems. However, it doesn’t kill the root system so repeat applications are needed. Don’t use this approach unless you can keep the vinegar confined only to the lily of the valley plants, as it will kill other nearby plants.

How to Get Rid of Lily of the Valley with Herbicides

If non-chemical methods fail to eradicate lily of the valley, you may need to turn to chemical control. Systemic herbicide products containing glyphosate or triclopyr can be effective when applied correctly:

• Carefully apply the herbicide directly only on the lily of the valley plants using a small paint brush or spray bottle. Avoid any contact with desired plants.

• Glyphosate products like Roundup can be applied any time the plants are actively growing.

• For triclopyr products, apply in fall when the plants are moving carbohydrates down into the roots.

• It will likely take several applications over multiple growing seasons to fully kill the root systems.

• Always follow the product labels exactly and take proper safety precautions.

5 Alternative Groundcovers to Plant Instead

Once you banish lily of the valley from your garden, you’ll need to plant something else in its place. Here are some great groundcover options that are easier to manage and not invasive:

• Epimediums: Delicate flowers and heart-shaped foliage. Does well in shade.

• Corsican Mint: Tiny leaves with minty scent. Tolerates shade.

• Creeping Phlox: Moss-like foliage and pretty spring blooms. Grow in sun or partial shade.

• Sweet Woodruff: Fragrant white spring flowers. Thrives in shade.

• Ajuga: Carpet-like foliage and blue flower spikes. Grow in sun or shade.

Preventing Lily of the Valley From Returning

Getting rid of the existing lily of the valley plants is only half the battle. You’ll also need to take steps to prevent it from re-establishing in the future:

• Monitor the area closely and stay vigilant for new sprouts. Quickly dig up or spot treat any you find before they get established.

• Put down a physical weed barrier like landscape fabric under mulch after removing the plants. This can prevent rhizomes and seeds from emerging.

• Solarize the soil periodically to kill seeds and rhizome pieces lurking below ground.

• Plant competitive groundcovers and perennials that will crowd out any lily of the valley sprouts.

• Avoid composting any lily of the valley plants or seeds. Bag them up and put in the trash instead.

The Bottom Line

Lily of the valley is notoriously difficult to get rid of once established in a garden. Eradicating it requires persistence and diligence to prevent it from making a comeback. Use a multipronged approach that includes manual digging, smothering, solarization and targeted use of herbicides. With time and dedication, you can rid your garden of this invasive plant and enjoy a lily of the valley-free landscape.