Zantedeschia 'Picasso' (Picasso calla lily) care

Light

Bright but filtered. Zantedeschia 'Picasso' burns within days in unfiltered south-facing summer sun, and stops growing within months in deep shade. Bright, filtered light indoors or full sun to light shade outdoors gives the best two-tone contrast and strong stems. Low light produces weak, floppy growth and few flowers. If you only have a south window, set the plant back 1.5 m or hang a sheer curtain — both knock the intensity down into the right range.

Watering

Watering zantedeschia 'picasso': when the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Keep compost evenly moist during leaf and flower production, letting the surface dry slightly between waterings, and never leave the pot waterlogged. Reduce watering after flowering and keep the rhizome nearly dry in winter dormancy.

Soil and pot

Zantedeschia 'Picasso' grows best in rich, moisture-retentive yet free-draining potting mix. A peat-free multipurpose compost with added perlite or grit, slightly acidic to neutral (pH 6.0-6.5). As with all coloured callas, sharp drainage protects the rhizome from rot. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Zantedeschia 'Picasso' sits happiest at around 40-60% humidity and 15-24°C (59-75°F). Average household humidity is adequate. Moderate humidity keeps foliage in good condition; avoid wetting the spathes, which marks the pale areas and risks botrytis. If you keep the room above 15 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed zantedeschia 'picasso' sparingly. Feed with a high-potassium liquid fertiliser every 2-3 weeks in active growth to support flowering and crisp spathe colour. Limit high-nitrogen feeds, which favour leaves. Stop feeding when the foliage begins to die back. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on zantedeschia 'picasso' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Rhizome rot — The most common killer; cold, wet compost rots the rhizome. Use free-draining mix, water moderately, and keep dry in dormancy.
• Loss of variegation/colour — Insufficient light flattens the purple-and-white contrast and the leaf spotting; move to brighter indirect light.
• Botrytis on spathes — Pale areas are prone to grey mould if water sits on them; water at the base and improve air circulation.
• Aphids — Gather on new shoots and flower stems; rinse off and treat with insecticidal soap before they distort growth or spread virus.

Propagation

Divide rhizomes in spring or at the onset of dormancy, ensuring each division has an eye; pot in free-draining mix and water lightly until shoots emerge. Named hybrids like 'Picasso' do not come true from seed. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Zantedeschia 'Picasso' is toxic to pets. Toxic to cats and dogs. The ASPCA lists calla lily (Zantedeschia) as toxic owing to insoluble calcium oxalate crystals in all parts; chewing releases needle-like raphides that cause oral burning, irritation of the mouth, tongue and lips, drooling, vomiting and difficulty swallowing. Keep away from pets. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Zantedeschia 'Picasso' deep-dive guides

Every aspect of zantedeschia 'picasso' care, each with its own calibrated guide:

• Zantedeschia 'Picasso' watering schedule
• Zantedeschia 'Picasso' light requirements
• Best soil mix for zantedeschia 'picasso'
• Zantedeschia 'Picasso' fertilizing guide
• When to repot zantedeschia 'picasso'
• How to propagate zantedeschia 'picasso'
• Zantedeschia 'Picasso' growth rate & size
• Zantedeschia 'Picasso' cold hardiness
• Zantedeschia 'Picasso' temperature & humidity
• Is zantedeschia 'picasso' toxic to cats & dogs?
• Is zantedeschia 'picasso' toxic to cats?
• Is zantedeschia 'picasso' toxic to dogs?
• Getting zantedeschia 'picasso' to bloom

Featured in these plant shortlists

Zantedeschia 'Picasso' qualifies for 3 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Houseplants toxic to cats & dogs — The common houseplants the ASPCA lists as toxic to cats and dogs — the ones to keep out of reach, each with its symptoms and a safe alternative.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Zantedeschia 'Picasso' is also commonly called Picasso calla lily or purple-edged calla.

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