Mature size & growth rate

How big does Black Calla Lily (Zantedeschia 'Black Star') get?

Also called Black Calla Lily, Black Star Calla.

More about black calla lily

About Black Calla Lily

Zantedeschia 'Black Star' · also called Black Calla Lily, Black Star Calla · flowering

Zantedeschia 'Black Star' is a striking hybrid calla lily producing intensely deep maroon-black spathes on tall stems above lush, dark green, sometimes spotted foliage. A highly sought-after cut flower and container plant, it thrives in full sun with consistent moisture during growth and a dry winter dormancy. All parts are toxic to cats, dogs, and humans due to calcium oxalate raphides.

Mature size: 60–90 cm tall in flower; spread 30–45 cm

Watch for — Aphids on new growth: Aphids cluster on emerging shoots and flower buds in spring. Blast off with a strong jet of water, or apply insecticidal soap. Ants tending aphid colonies on outdoor plants indicate an infestation — use a sticky barrier on pot legs.

Indoor size vs how big it gets in the wild

Black Calla 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 60–90 cm tall in flower. In the ground with no restriction it is a completely different plant — spread 30–45 cm — which is why the pot, the light and the pruning matter so much for the size you actually end up with.

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

Black Calla Lily 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: apply a high-potassium liquid fertiliser (tomato feed formula) every 2 weeks from when shoots emerge until the flower spathes begin to fade. this promotes the deep pigmentation and strong stem development the cultivar is selected for. switch to a balanced feed at planting if soil has not been pre-enriched.

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

How to keep black calla lily smaller

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

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

If you want it to fill the space sooner, push the conditions rather than hoping — for black calla 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 black calla lily light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When black calla lily outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for black calla 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 black calla lily repotting guide. If you want more of this plant instead of a bigger one, the black calla lily propagation guide turns prunings into new plants.

Black Calla Lily size — frequently asked questions

How big does black calla lily get?

Black Calla Lily reaches 60–90 cm tall in flower when grown indoors, and far larger where it grows unrestricted (spread 30–45 cm). 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 black calla lily slow or fast growing?

Black Calla Lily is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Black Calla 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 black calla lily 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 black calla lily smaller?

Divide the clump every year or two — splitting black calla 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 black calla 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.