Lily of the valley: planting rhizomes in autumn, care and toxicity

Autumn planting and dividing of lily of the valley, care through the year and everything important about its toxicity, including confusion with wild garlic.

In brief: Plant lily of the valley in autumn, from September to October, as rhizomes with buds 2–3 cm below the surface and 10–15 cm apart. It wants shade or partial shade and humus-rich moist soil. It flowers in May and spreads quickly. The whole plant, including the berries and the water from the vase, is highly poisonous.

Latin name	Convallaria majalis, Asparagaceae
Planting	September–October, as a last resort early in spring
Depth and spacing	buds 2–3 cm below the surface, 10–15 cm apart
Flowering	May, height 15–25 cm
Position	shade to partial shade, humus-rich moist soil
Toxicity	cardiac glycosides, the whole plant, people and animals

Lily of the valley is a perennial for places where other plants struggle: under trees, by a north wall, among shrubs. Once planted, it spreads by itself with rhizomes, forms a continuous carpet and every May scents the air for metres around.

It has a second face, however. It is among the most poisonous plants that commonly grow in gardens, and in spring its leaves are easily mistaken for edible wild garlic. Autumn is at the same time the ideal time to plant and divide lily of the valley, so we start with planting and deal with safety in detail in the second half.

Where to plant lily of the valley (and where rather not)

Lily of the valley feels best in partial shade under deciduous trees and shrubs, in humus-rich, loose and slightly moist soil. It also tolerates deep shade, but flowers less there. In full sun and in dry sandy soil the leaves scorch in summer and the plant weakens. You can find tips on other plants for shade in the article which plants suit the shade.

Count on it spreading. In an open space under trees this is an advantage; in a mixed bed it can outgrow its neighbours. If you want to keep it in place, sink a strip of plastic or an edging 20 cm deep around the planting. Do not plant it near a sandpit, a children's playground or a dog run. Among ornamental perennials for shade it is one of the most reliable, it just needs a place out of reach of children and animals.

When and how to plant the rhizomes

The best time is September and October. The soil is still warm and moist, the rhizomes root before winter and grow fully in spring. The same date applies to dividing old clumps. Early in spring, in March, it also works, but in the first year lily of the valley often only produces leaves.

Wear gloves when working and do not leave the rhizomes lying where a dog or child could find them.
Loosen the soil to a depth of 20 cm, remove weed roots and mix in compost or leaf mould.
Briefly soak the rhizomes with buds (also sold as "pips") in lukewarm water so that they take up moisture.
Lay them horizontally or at an angle, buds upwards, 2–3 cm below the surface. Space them 10–15 cm apart; 25–40 pieces per square metre is enough.
Cover, press down lightly and water thoroughly.
Mulch the surface with a layer of leaves or compost, which holds moisture and rots down by spring.

When dividing your own clump, lift it with a digging fork, divide it by hand into pieces with several buds and replant them at once. A digging fork damages the rhizomes less than a spade.

Care through the year

Spring: water in a dry April and May; during flowering the plant is most demanding on water.
Summer: at the end of summer the leaves turn yellow and the clumps look untidy. Do not cut them until they dry, as the plant stores reserves from them. Tall perennials in the shade, for example hostas or ferns, will cover them.
Autumn: add 2–3 cm of compost or leaf mould. Lily of the valley needs no other feeding.
After 4–5 years: when the clumps become dense and flower less, divide them in autumn.

In summer, after flowering, red berries ripen. If you have small children, cut off the spent flower stems right after flowering, and the berries will not form at all.

Lily of the valley in a pot and in a vase

Lily of the valley can also be grown in a deeper pot. In autumn plant rhizomes in it, leave it outdoors in the cold so that it goes through winter, and in February move it to a bright cool room. It will flower a few weeks earlier than in the garden. After flowering, plant the plants outdoors.

Cut lily of the valley in a vase scents the whole room. The poisonous substances, however, also pass into the water in the vase, so put the vase where neither a child nor a cat can reach it, and pour the water down the sink, not into an animal's bowl.

Toxicity: children, dogs, cats

Lily of the valley contains cardiac glycosides, mainly convallatoxin. They act on the heart: besides nausea and vomiting they can cause an irregular pulse, a drop in blood pressure, confusion and in severe cases danger to life. All parts of the plant are poisonous: flowers, leaves, rhizomes, red berries and the water from the vase.

Dogs and cats react similarly: with vomiting, heart rhythm disturbances, low blood pressure, disorientation and, in severe cases, convulsions. If you suspect poisoning of a child or an adult, call 155 or the Toxicological Information Centre on 224 919 293 or 224 915 402, even if there are no symptoms yet. For an animal go to the vet at once. Do not induce vomiting and take the rest of the plant with you. Other poisonous plants commonly grown for decoration, such as thorn apple, oleander or yew, are described in the article poisonous ornamental plants.

Beware of confusion with wild garlic

In spring, in April, the young leaves of lily of the valley resemble the leaves of wild garlic. Confusion happens in the Czech Republic every spring, yet the differences are clear:

Feature	Lily of the valley	Wild garlic
how the leaves grow	usually two leaves from one stem, the lower part wrapped in a sheath	each leaf on its own stalk straight from the ground
smell of a crushed leaf	no garlic smell	distinctly garlicky
flower	white bells in a one-sided raceme	white stars in an umbel

If you grow both, put them at opposite ends of the garden and pick leaf by leaf. Do not rely on the smell on your fingers: after a while of picking your hands smell of garlic and then every leaf seems to smell. We will deal with growing wild garlic and telling the two plants apart in detail in a separate guide.

Frequently asked questions

When should I plant lily of the valley?

Best in September and October, when the rhizomes root before winter. March also works, but in the first year the plant often only produces leaves. Old clumps are divided at the same autumn time.

Is lily of the valley poisonous to dogs and cats?

Yes, highly. It contains cardiac glycosides that cause vomiting, heart rhythm disturbances and a drop in blood pressure. If you suspect an animal has chewed lily of the valley or drunk water from the vase, go to the vet at once.

Is lily of the valley protected?

In the Czech Republic it is not a specially protected species, and you may grow and pick it in the garden. In national parks, nature reserves and other protected areas, however, plants must not be collected, and nowhere should you dig whole clumps out of the wild.

Why does lily of the valley not flower?

Most often because of too deep shade, an overcrowded clump or drought during flowering. Divide an old clump in autumn and replant it in partial shade; young plantings usually flower fully only in the second year.

How do I get rid of lily of the valley in the garden?

Dig the clumps out with a digging fork together with the rhizomes and pick out even small pieces from the soil, from which lily of the valley sprouts again. The job usually has to be repeated the next season. Work in gloves and do not put the rhizomes on a compost heap where animals can reach them.

Sources

Updated: 27 September 2026

Author: Jana Vránová, the editorial name of the Pěstík.cz team. She writes about the garden, herbs and essential oils. We take safety and dosage information from specialist literature and official sources, which we cite in every article.