Calla lily

Sun

Full sun to partial shade; give afternoon shade in hot, dry climates.

Water

Keep consistently moist during active growth; established plants tolerate boggy soil and shallow pond margins. Reduce watering if the leaves die back and the plant becomes dormant.

Soil

Rich, moisture-retentive soil with plenty of organic matter; tolerates heavy soil and seasonal waterlogging.

Height

2-4 ft (0.6-1.2 m)

Spread

2-3 ft (0.6-0.9 m), eventually wider where spreading rhizomes are not contained

Flowers

White spathes with yellow central spikes, mainly in late spring and summer; flowering can begin earlier or continue longer in mild climates.

Foliage

Large, glossy green, arrow-shaped leaves, usually without spots. Evergreen in mild, moist conditions, but dies back after frost or during dry-season dormancy.

Growth

Moderate to fast in warm, moist conditions

Care needed

Medium

• Water deeply enough to keep the root zone moist while leaves are growing; do not let containers dry out.
• Work compost into the soil in spring and apply a balanced fertiliser at the label rate as growth starts.
• Mulch the crown generously before winter near the colder end of its hardiness range.
• Where winters are colder than its range, grow in a movable pot or lift the rhizomes before hard frost and store frost-free.
• Divide crowded clumps in spring, keeping a healthy growing point and roots on each section.
• Remove developing seed heads and contain rhizomes where the plant spreads readily; check local weed restrictions before planting.

Pruning. Cut spent flower stems near the base and remove yellow or frost-damaged leaves as needed. Leave healthy green foliage intact so it can replenish the rhizomes.

Early spring

Remove winter-damaged leaves and check crowns for soft, rotting tissue.

Spring

Divide crowded clumps, top-dress with compost and feed as new growth begins.

Late spring

Move overwintered containers outdoors after frost risk has passed, introducing them gradually to direct sun.

Summer

Maintain steady moisture, especially in pots, and cut off fading flower stems.

Autumn

Remove seed heads before berries ripen and lift or shelter plants where winters are too cold.

Winter

Maintain protective mulch outdoors; keep stored dormant rhizomes frost-free and check periodically for rot.

• Plant beside a pond or in a managed bog garden for bold foliage and upright white flowers.
• Use a single large container as an architectural accent beside a terrace or doorway.
• Repeat clumps through a white garden with ferns and shade-tolerant foliage plants.
• Combine with large-leaved perennials in a sheltered, moist border for a lush effect.

Garden styles it suits: Architectural minimal, Bog garden, White garden, Modern tropical, Modern courtyard and Tropical.

Plant it with: Royal fern, Hosta, Astilbe, Japanese iris, Ligularia and Japanese sedge.

Wildlife: Flowers attract some insects, but this is not a dependable nectar plant for a pollinator border. In regions where it escapes cultivation, dense stands can displace native wetland vegetation.

• Slugs and snails chew young leaves: inspect new growth, remove pests and use wildlife-conscious slug controls where needed.
• Aphids gather on tender shoots: wash them off with water or use insecticidal soap according to the label.
• Soft rot causes collapsing stems and foul-smelling, mushy rhizomes: discard affected material, clean tools and avoid damaged rhizomes or stagnant, warm growing conditions.
• Few flowers often result from deep shade, drought or excessive nitrogen: improve light, maintain moisture and avoid repeated high-nitrogen feeding.

All parts are toxic to people, cats, dogs and horses if chewed or eaten. Insoluble calcium oxalate crystals cause immediate burning, mouth swelling, drooling and difficulty swallowing; severe swelling can occasionally threaten breathing. Sap can irritate skin and eyes. Seek medical or veterinary advice after ingestion, urgently if breathing or swallowing is affected.

Where it spreads. An invasive environmental weed in parts of Australia, notably Western Australia, South Australia, Victoria and Tasmania, and in New Zealand. It also escapes and invades wet habitats in parts of coastal California. It spreads by rhizomes and seed; check local restrictions and do not dump garden waste near waterways.

• Peace lily (Spathiphyllum spp.)

  Also has a white spathe and central spike, but its leaves are oval to lance-shaped with prominent veins rather than distinctly arrow-shaped. It is generally grown as a houseplant in temperate climates.

• Yellow calla lily (Zantedeschia elliottiana)

  Has yellow rather than white spathes and usually white-spotted leaves. It is more tender and needs a drier dormant period than white calla lily.

• Italian arum (Arum italicum)

  Usually has pale-veined leaves, a greenish flower hood and conspicuous spikes of orange-red berries. It is smaller and typically loses its leaves in summer.

Zantedeschia honours the Italian botanist Giovanni Zantedeschi.

Propagation. Divide established rhizome clumps in spring as growth resumes. Seed is possible but slower and can produce variable plants; avoid seed propagation where the species is invasive.

Accepted botanical name

Zantedeschia aethiopica

In the US and Canada

Introduced in Hawaii, the lower 48 states and Puerto Rico.

Native range

Cape Provinces, Free State, KwaZulu-Natal, Lesotho, Northern Provinces and Swaziland.

Measured

Average height 40 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.