Lily of the valley is deceptive. The elegant, sword-shaped leaves and delicate little bell-like blossoms look sweet as can be.
Brides carry them in bouquets and they often feature in posies. But Convallaria majalis is anything but unassuming and demure.
Beyond being incredibly tough in the garden, able to thrive and spread in conditions that would topple most plants, they’re also incredibly potent. The plants contain compounds that can be deadly.
If you were wondering whether your dog might be in trouble after running around with a lily of the valley in its mouth or if your cat should go to the vet after nibbling on the leaves, the answer is yes.
The same applies if your child thought the sweet-smelling flowers would make a nice snack. Pets and humans should never put any part of this plant in their mouths.
But there’s more to the story than that as this plant has the potential to be a powerful medicine.
So if you’re curious to learn more about lily of the valley toxicity, let’s discuss the following:
What You’ll Learn
Just to clarify, the terms poisonous and toxic are being used interchangeably here. Poison describes a substance that can cause harm.
A toxin is just a naturally-occurring poison. Some people call toxins produced by living sources biotoxins.
What Is Lily of the Valley?
Lily of the valley is a low-growing plant found throughout the northern hemisphere.
A member of the asparagus family (Asparagaceae), this species originated in Europe and Asia, with possible native populations in eastern North America – though this remains debated.
The plant has spread rapidly across the globe in non-native regions, thriving in areas equivalent to USDA Hardiness Zones 3 to 9.
True to its reputation as an aggressive spreader, lily of the valley flourishes in the shady, moist conditions it prefers, though it can form extensive colonies even in less-than-ideal climates.
The plant features a rosette of sword-shaped leaves, and in spring, stalks of fragrant white or pink bell-shaped flowers emerge.
Lily of the valley is a popular choice for shaded garden spots, though it adapts well to brighter conditions.
It typically reaches up to a foot tall and spreads as widely as conditions allow, with individual plants measuring about six to eight inches across.
Our guide to growing lily of the valley has more information.
Is It Poisonous?
In a word: yes.
C. majalis can definitely be toxic and there are documented cases of both people and pets being harmed by ingestion.
While rarely fatal, consuming lily of the valley could potentially kill a person or animal.
However, as Swiss theologian and physician Paracelsus theorized, “the dose makes the poison” – small amounts of potentially toxic substances might have beneficial properties.
This principle certainly applies to lily of the valley. The same compounds that make it dangerous can also be beneficial.
Researchers are investigating ways to use C. majalis to treat kidney problems, heart conditions, and cancer, though the glycosides used medicinally are typically synthesized in laboratories rather than extracted from plants.
Some people attempt to self-treat health issues with these plants, but there’s no reliable evidence that lily of the valley provides benefits when used this way – only substantial evidence of its potential harm.
Cases have also been reported of people consuming lily of the valley after mistaking it for wild leeks, or ramps (Allium tricoccum).
This serves as an important reminder: never eat foraged plants unless you are absolutely certain of their identity.
What Makes the Plant Toxic?
Lily of the valley contains cardiac glycosides, with 38 known cardenolide glycosides including convallatoxin, convallarin, and convallatoxol.
The plant also contains saponins, which are toxic in their own right, though the glycosides occur in higher concentrations.
These cardiac glycosides affect the heart, causing arrhythmias, changes in blood clotting, fluctuations in blood pressure, and alterations in heart rate.
The chemical composition varies from plant to plant and even between different parts of the same plant.
Older plant tissue typically contains higher concentrations of active compounds, with roots being the most potent.
The flowers contain numerous volatile organic compounds, including citronellol, geraniol, benzyl alcohol, phenylacetonitrile, and farnesol.
Any of these can be toxic in large doses. Interestingly, citronellol and geraniol serve dual purposes – we use them as pesticides, but also as fragrances and ingredients in cosmetics.
The berries present a particular hazard because they resemble edible berries like currants, making them a source of accidental poisoning, especially among children.
These toxic compounds likely evolved as the plant’s defense mechanism against feeding herbivores. They also play a role in the plant’s production of vitamin D and essential growth hormones.
Symptoms of Poisoning
When any part of C. majalis is ingested, the glycosides are absorbed and impact cell membranes rapidly.
Shortly after ingestion, individuals may experience arrhythmia, changes in blood pressure or heart rate, and potentially fatal heart failure.
Other symptoms include nausea, stomach pain, vomiting, fainting, and diarrhea.
Additional symptoms can also include increased urine output, vision changes, confusion, depression, lethargy, headache, and weakness.
Some people may develop a rash, blisters, or itching from skin contact with the plant.
If you suspect you’ve ingested lily of the valley, call poison control at 800-222-1222. If your pet has consumed the plant, seek veterinary care immediately.
Treatment may include activated charcoal, digoxin, IV fluids, and medications to address nausea, diarrhea, and other symptoms.
Look, Don’t Touch
If you have curious pets or children who can’t seem to stay out of the garden, lily of the valley may not be the right choice for your landscape at this time.
However, if you live in a suitable climate and can ensure that your loved ones – animals included – won’t be sampling your Convallaria, it makes a beautiful, adaptable, and low-maintenance garden option.
Are you growing this plant? Are you considering planting it, or perhaps thinking about removing it? Let us know in the comments section below!
If you’re planning to grow lily of the valley in your garden, you might want to learn more about how to care for it. Here are some additional guides to check out next:
