Mature size & growth rate

How big does Lily of the valley (Convallaria majalis) get?

Also called May lily, May bells, our lady's tears.

About Lily of the valley

Convallaria majalis · also called May lily, May bells · flowering

Lily of the valley is a shade-loving perennial with broad green leaves and tiny fragrant white bells in late spring. Spreads by rhizome to make ground cover. Severely toxic to pets and people — every part contains cardiac glycosides.

Convallaria majalis is a rhizomatous herbaceous perennial of Europe and Central Asia (naturalized in temperate North America and invasive in parts of the northern US), forming a low 8–12 in groundcover of arching white bells.

Spreads aggressively by rhizome into dense colonies, becoming weedy/invasive in good conditions. SEVERELY toxic: all parts contain cardiac glycosides — primarily convallatoxin — causing arrhythmia, blood-pressure/heart-rate changes and potentially fatal heart failure; even vase water has killed pets. Wear gloves and site away from children and animals.

Mature size: 15-25 cm tall

Watch for — Aggressive spread: Rhizomes run; install a rhizome barrier or grow in containers.

Sources: missouribotanicalgarden.org, pmc.ncbi.nlm.nih.gov

Indoor size vs how big it gets in the wild

Lily of the valley stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward. Indoors and in a pot, expect 15-25 cm tall. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Growth rate and years to mature

Lily of the valley is a moderate grower. Realistically, expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Its feeding profile backs this up: leaf-mould top-dress in spring.

Want this turned into the right next pot at the right moment? The pot size calculator and the lily of the valley repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast lily of the valley grows.

How to keep lily of the valley smaller

You are not stuck with the maximum size. For lily of the valley specifically, these are the levers, in order of impact:

Divide the clump every year or two — splitting lily of the valley is the main way to control its spread and refresh it.
Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump.
Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

The keep-it-smaller method, step by step

Lift the whole plant. Slide lily of the valley out of its pot in spring when the clump has filled it.
Split the clump. Tease or cut the rootball into two or more sections, each with healthy roots and growth.
Repot one division. Put a single division back in the original pot to reset it to a smaller size; pot or give away the rest.
Remove offsets as they form. Through the year, detach new runners or pups to stop it spreading again.

How to grow lily of the valley bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for lily of the valley the accelerators are:

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Brighter light speeds up clump and offset production noticeably.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

Light is almost always the ceiling. The lily of the valley light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When lily of the valley outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for lily of the valley:

The clump bulging over the pot rim or splitting the pot — the cue to divide, not to find a bigger room.
A dense centre that goes bare or tired while the edges keep spreading.
Runners or offsets escaping across the shelf or into neighbouring pots.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the lily of the valley repotting guide. If you want more of this plant instead of a bigger one, the lily of the valley propagation guide turns prunings into new plants.

Lily of the valley size — frequently asked questions

How big does lily of the valley get?

Lily of the valley reaches 15-25 cm tall when grown indoors. Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Is lily of the valley slow or fast growing?

Lily of the valley is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Lily of the valley stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward.

How long does lily of the valley take to reach full size?

Roughly three to six years to reach mature indoor size, gaining a steady amount each growing season. Light, pot size and feeding move that timeline more than anything else.

How do I keep lily of the valley smaller?

Divide the clump every year or two — splitting lily of the valley is the main way to control its spread and refresh it. Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump. Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

How can I make lily of the valley grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Brighter light speeds up clump and offset production noticeably. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.