Mature size & growth rate

How big does Arum Lily (Zantedeschia aethiopica) get?

Also called Arum Lily, Calla Lily, White Calla, Pig Lily.

More about arum lily

About Arum Lily

Zantedeschia aethiopica · also called Arum Lily, Calla Lily · flowering

Zantedeschia aethiopica is a robust, rhizomatous perennial native to stream banks, marshes, and moist meadows in southern Africa, producing large, pure-white spathe flowers surrounding a yellow spadix from late winter to early summer. It thrives in moist to wet, humus-rich soil in full sun to part shade and can be grown as a marginal aquatic with roots in shallow water. In the UK it is hardy enough to overwinter outdoors in most areas with mulch protection; in colder climates (USDA zones below 8) lift rhizomes and store frost-free. All parts are toxic to cats and dogs.

Mature size: 90–120 cm (3–4 ft) tall and 60–90 cm (2–3 ft) wide at full maturity.

Indoor size vs how big it gets in the wild

Arum Lily 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 90–120 cm (3–4 ft) tall and 60–90 cm (2–3 ft) wide at full maturity.. 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

Arum Lily is a fast grower. Realistically, expect two to four years from a young plant to a room-filling specimen in good light. Its feeding profile backs this up: feed every 2–3 weeks from spring until flowering ends with a high-potassium liquid fertiliser (tomato feed is ideal) to support large, waxy flowers; stop feeding once foliage yellows in late summer.

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

How to keep arum lily smaller

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

Divide the clump every year or two — splitting arum lily 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 arum lily 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 arum lily bigger or faster

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

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Good light plus regular feeding maximises offset and runner production.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

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

When arum lily outgrows the room (or the pot)

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

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 arum lily repotting guide. If you want more of this plant instead of a bigger one, the arum lily propagation guide turns prunings into new plants.

Arum Lily size — frequently asked questions

How big does arum lily get?

Arum Lily reaches 90–120 cm (3–4 ft) tall and 60–90 cm (2–3 ft) wide at full maturity. 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 arum lily slow or fast growing?

Arum Lily is a fast grower. Expect two to four years from a young plant to a room-filling specimen in good light. Arum Lily 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 arum lily take to reach full size?

Roughly two to four years from a young plant to a room-filling specimen in good light. Light, pot size and feeding move that timeline more than anything else.

How do I keep arum lily smaller?

Divide the clump every year or two — splitting arum lily 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 arum lily grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Good light plus regular feeding maximises offset and runner production. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.