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Water Lily Cactus (Easter Lily Cactus) care

Echinopsis eyriesii

Also called Easter Lily Cactus, Sea Urchin Cactus, Hedgehog Cactus.

RHS H2USDA 9-11Pet-safeIndoor 15-25 cm tall and 10-15 cm wide per head

Watering rhythm

7-10days

When the top 2-3 cm of soil is dry, roughly every 7-10 days in spring and summer; every 3-4 weeks in autumn; almost none in winter

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Light

Bright indirect light (just back from a sunny window)

Soil

Free-draining cactus or succulent mix with 30-40% perlite

Humidity

30-50%

Temp

5-30°C

Pet safety

Pet-safe

Mature size

15-25 cm tall and 10-15 cm wide per head

Care at a glance

Light

Bright but filtered. Water Lily Cactus burns within days in unfiltered south-facing summer sun, and stops growing within months in deep shade. Produces the most flowers with bright light including some direct morning sun. A few hours of direct sunlight plus bright indirect light for the remainder suits it well. Avoid harsh afternoon sun through glass in summer, which can scorch the body. 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 water lily cactus: when the top 2-3 cm of soil is dry, roughly every 7-10 days in spring and summer; every 3-4 weeks in autumn; almost none in winter. 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. A cool, dry winter rest is essential for flower bud initiation. Resume watering in early spring as temperatures rise. During flowering keep the soil slightly more moist but never waterlogged. Use room-temperature water.

Soil and pot

Water Lily Cactus grows best in free-draining cactus or succulent mix with 30-40% perlite. Standard cactus compost blended with perlite provides adequate nutrition while ensuring rapid drainage. Repot every 2-3 years into a slightly larger container, refreshing the compost at the same time. 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

Water Lily Cactus sits happiest at around 30-50% humidity and 5-30°C (41-86°F). Tolerates a wide range of indoor humidity levels. Normal household conditions are perfectly adequate. Avoid overly dry heated air near radiators during winter, which can desiccate the plant body. If you keep the room above 5 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 water lily cactus sparingly. Apply a dilute potassium-rich cactus or tomato fertiliser (e.g. 5-10-10) monthly from spring through early autumn to support flowering. Do not feed in winter. 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 water lily cactus in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Failure to flower — Requires a cold, dry winter rest (5-10°C) to set flower buds. Plants kept warm and watered through winter rarely bloom the following year.
  • Basal rot — Excess moisture at the crown leads to soft rot. Ensure drainage is excellent and the base is never sitting in water.
  • Mealybugs — White fluff in spine axils or between offsets. Remove with alcohol swabs and treat systemically if the infestation persists.
  • Overcrowding of offsets — Dense pups can crowd the mother plant and impede air circulation. Remove some offsets and pot them separately to encourage vigorous growth.
  • Sunscorch — Pale or brownish patches after moving to direct sun. Acclimatise gradually and avoid intense midday sun through glass in summer.

Companion plants

Water Lily Cactus pairs well with Rebutia muscula, Parodia leninghausii, and Echinopsis pachanoi. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Offsets (pups) can be carefully detached from the mother plant with a clean knife, allowed to callous for 2-3 days, and potted in dry cactus mix. Also grows easily from seed at 20-25°C. 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

Water Lily Cactus is pet-safe. Echinopsis eyriesii is not individually listed by the ASPCA, but the Echinopsis genus is classified among true cacti that are generally non-toxic to dogs and cats. Physical spine injury is the primary risk to curious 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.

Water Lily Cactus care — frequently asked questions

What is the common name for Echinopsis eyriesii?

Echinopsis eyriesii is most commonly called Water Lily Cactus, but it is also known as Easter Lily Cactus, Sea Urchin Cactus, Hedgehog Cactus. The names refer to the same species, so care instructions for Water Lily Cactus apply identically to anything sold as Easter Lily Cactus.

How much light does water lily cactus need?

Water Lily Cactus grows best in bright indirect light (just back from a sunny window). Produces the most flowers with bright light including some direct morning sun. A few hours of direct sunlight plus bright indirect light for the remainder suits it well. Avoid harsh afternoon sun through glass in summer, which can scorch the body.

How often should I water water lily cactus?

Water water lily cactus when the top 2-3 cm of soil is dry, roughly every 7-10 days in spring and summer; every 3-4 weeks in autumn; almost none in winter. A cool, dry winter rest is essential for flower bud initiation. Resume watering in early spring as temperatures rise. During flowering keep the soil slightly more moist but never waterlogged. Use room-temperature water. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is water lily cactus toxic to cats and dogs?

Water Lily Cactus is pet-safe. Echinopsis eyriesii is not individually listed by the ASPCA, but the Echinopsis genus is classified among true cacti that are generally non-toxic to dogs and cats. Physical spine injury is the primary risk to curious pets.

What USDA hardiness zone does water lily cactus grow in?

Water Lily Cactus is rated for USDA zone 9-11 and RHS hardiness H2. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Water Lily Cactus deep-dive guides

Every aspect of water lily cactus care, each with its own calibrated guide:

Featured in these plant shortlists

Water Lily Cactus qualifies for 12 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

  • Best pet-safe houseplants — Houseplants the ASPCA lists as non-toxic to cats and dogs — every one verified against the ASPCA toxic and non-toxic plant list.
  • 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.
  • Best pet-safe flowering plants — Flowering houseplants the ASPCA lists as non-toxic to cats and dogs — colour and blooms in a pet home, without the worry.
  • Best pet-safe plants for bright light — Non-toxic to cats and dogs and happy in a bright, sunny spot — safe plants for your best-lit windowsill.
  • Best succulents for beginners — The easiest succulents and cacti to keep alive — selected by documented growth habit, each with the light and watering it actually wants.
  • Best pet-safe succulents — Succulents the ASPCA lists as non-toxic to cats and dogs — low-water greenery that is also safe around a curious pet.
  • Best small & tabletop houseplants — Compact houseplants that stay under about 40 cm — desk, shelf and windowsill plants that never outgrow a small space.
  • Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
  • Best cat-safe plants — Houseplants the ASPCA lists as non-toxic to cats (and dogs) — safe greenery for a home with a curious cat.
  • Best dog-safe plants — Houseplants the ASPCA lists as non-toxic to dogs (and cats) — safe greenery for a home with a curious dog.
  • Best small pet-safe plants — Compact, tabletop houseplants that are also ASPCA non-toxic to cats and dogs — safe greenery for a desk or shelf.
  • Browse all 30 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Water Lily Cactus is also known as Easter Lily Cactus, Sea Urchin Cactus, and Hedgehog Cactus.