Zantedeschia pentlandii (Pentland's calla) care

Light

Zantedeschia pentlandii is what florists mean by "bright spot, no direct sun" — close enough to a south or east window to feel the brightness, with a sheer curtain or a few feet of distance keeping the sun off the leaves. Thrives in bright light: full sun to part shade outdoors, or a very bright spot indoors. Good light is needed for reliable flowering and the deep yellow spathe colour; deep shade gives sparse blooms. A phone lux-meter at the leaf surface should read 1,500-3,000 lux at noon.

Watering

Water zantedeschia pentlandii when the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Water freely to keep compost evenly moist through leaf and flower production in spring and summer, but never waterlogged. As foliage yellows in late summer, taper off and keep the dormant tuber dry until growth restarts.

Soil and pot

Zantedeschia pentlandii grows best in fertile, free-draining loam-based or multipurpose mix. Use a rich but sharply drained mix, slightly acidic to neutral. Unlike the bog-loving white arum (Z. aethiopica), this summer-rainfall species needs free drainage and resents wet, cold soil during dormancy. 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 pentlandii sits happiest at around 40-60% humidity and 15-25°C (59-77°F). Average humidity is suitable. It tolerates the drier air of a sunny windowsill or open garden well during its active season and prefers airflow over stagnant, humid conditions. 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 pentlandii sparingly. Feed every 2-3 weeks during active growth with a balanced-to-high-potassium liquid feed to support flowering. Reduce nitrogen as flowering approaches. Stop feeding once the leaves die back for the dry dormant period. 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 pentlandii in the Growli community. Each is annotated with the most common cause so you know where to start.

• Tuber rot — Cold, wet soil during dormancy is the main risk; keep the dormant tuber dry and grow in free-draining mix during the season.
• Poor flowering — Too little light or an immature/overcrowded tuber reduces blooms; give a brighter position and divide congested clumps.
• Yellowing in late summer — Natural onset of dormancy; reduce water and let the foliage die down rather than treating it as a problem.
• Spider mites and aphids — Sap-suckers attack foliage and flower stems in warm, dry spells; inspect regularly and treat early with insecticidal soap.

Propagation

Increase by dividing tubers/offsets during dormancy, each with a growing point, or by seed (which may vary). Pot divisions in free-draining mix and resume watering as new growth appears. 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 pentlandii is toxic to pets. Toxic to cats and dogs. The ASPCA classifies calla lily (Zantedeschia) as toxic because of insoluble calcium oxalate crystals in all parts; chewing causes oral irritation, intense burning 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 pentlandii deep-dive guides

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

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

Featured in these plant shortlists

Zantedeschia pentlandii 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 pentlandii is also commonly called Pentland's calla or yellow arum.

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