Bulb · Araceae
Calla Lily
Zantedeschia aethiopica
Hand it rich, wet ground and full sun, and the calla fires up tall, sculptural blooms.
Full sun
Every 2–4 days
USDA 8–10
2–3 ft · 0.6–1 m
Overview
The calla lily flaunts one of the cleanest shapes a garden can offer: a single curled spathe wrapped tight around a slim golden spike. Forget the name for a second, because it is no true lily but a card-carrying member of the arum family, native to southern Africa and grown the world over for cut stems and knockout summer beds. Pure white leads the pack, while the wider clan throws in cream, yellow, and deep wine tones to chase.
It powers up from a fat underground rhizome and storms back year after year in mild regions. Here is the trait that gets growers excited: this plant chases wet feet instead of dry, flipping the usual bulb rulebook. Plant it in boggy ground or right at a pond edge, let it stand in water up to about a foot deep, and watch the old overwatering worry vanish during active growth.
Striking as it is, the whole plant comes toxic to people and animals, so the enthusiasm stops at the mouth. Every part packs sharp calcium oxalate crystals that burn the moment they are bitten, making this a flower to feast your eyes on, never your taste buds. Plant it where pets and small children cannot grab the leaves or the sap, and enjoy the show.
Care
The short version: full sun to part shade, soil kept rich and reliably moist, a balanced feed through the growing months, and the rhizomes split every year or two once the clump packs out.
Light
Callas push their best flowers in full sun, yet they take partial shade in stride, which saves the day where summers run hot. Load them up with light and the blooms come back stronger and more upright.
Water
This plant drinks hard and loves it. Hold the soil consistently moist to boggy and water every 2 to 4 days through active growth, never once letting it dry out. It even shrugs off standing water up to about a foot deep, so going damp is the winning play.
Soil
Set it into rich, humusy clay or loam stacked with organic matter. Where other bulbs sulk, the calla powers through poor drainage and the odd flood, and it rolls with any pH from 6.0 to 8.0.
Temperature
It ranges across roughly 10°F to 86°F (-12°C to 30°C), hitting its stride in mild summer warmth. Hard freezes knock it into dormancy, so lift the rhizomes or heap on heavy mulch where winters bite.
Humidity
Callas thrive on air that runs humid, right in line with their love of damp ground and pond margins. Dry air alone will not stop them, so long as the soil stays moist.
Feeding
Feed monthly straight through spring and summer while growth charges ahead, reaching for a balanced general-purpose fertilizer. Dial it back as the foliage fades and the plant winds toward dormancy.
Pruning
Clip off spent flower stalks and any yellowing or dead leaves to keep the clump crisp. Once the foliage drops for the season, cut it back as the plant slides into dormancy.
Repotting
Divide and repot every 1 to 2 years, or jump in sooner once the clump packs itself tight. Rhizomes stuffing the pot, a thinner flower count, and roots punching out the drainage holes all shout that it is go time.
Size & spacing
A grown calla shoots up 2 to 3 feet (61 to 99 cm) tall and spreads 12 to 24 inches (30 to 61 cm) wide. Space the rhizomes about 12 to 18 inches (30 to 46 cm) apart so each clump has room to fill in fast.
When to plant
Callas wake up the moment warmth rolls in, so let the season set the pace. In cold-winter areas, start the rhizomes indoors in late winter, then send them outside once frost clears out. Flowers burst on in early summer, hitting full stride through June and July.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Start rhizomes indoors in late winter to early spring in cold-winter areas.
- Plant: Plant rhizomes outdoors in spring after frost, 3-4 inches deep and 12-18 inches apart.
- Harvest: Blooms June to July.
Hardiness
USDA hardiness zones: 8–10
Temperature: down to -12°C
Troubleshooting
Most calla trouble brews down in the soil or surfaces on the leaves, and nearly all of it bends to a quick response. Rot from waterlogged ground is the real threat to chase down, while beetles and thrips just pester. Spot your symptom below and pounce early.
Soft, mushy rhizome and collapsing leaves
A soft, mushy rhizome with leaves caving in spells rhizome rot, which takes off when soil stays waterlogged and starved of air. Lift the rhizome, give it a hard look, and toss any brown, foul-smelling tissue. On a rhizome still worth saving, slice off the soft spots, let the cuts cure, then replant in better-drained ground and get it growing again.
Fix:
- Lift affected rhizomes and discard rotted ones
- Cut away soft tissue from salvageable rhizomes and let cure
- Replant healthy rhizomes in better-drained, aerated soil
Leaves chewed to lace and flowers torn up
Leaves shredded to lace and flowers ripped up flag Japanese beetles, those metallic green-bronze insects that swarm foliage and blooms all summer. Knock them off by hand into a tub of soapy water. Stay relentless on a plant that is getting hammered, because clearing them early means far fewer roll in to feed.
Fix:
- Handpick beetles into soapy water
- Reduce populations on heavily infested plants
Silvery, stippled patches on the leaves
A silvered, speckled finish on the leaves, often dotted with black frass underneath, points to tiny banded greenhouse thrips rasping at the surface. Strip off and bin the worst-hit foliage to cut the load. Then keep the plant well fed and watered, since a vigorous calla powers right past light thrips damage.
Fix:
- Remove and dispose of heavily infested foliage
- Improve growing conditions to support plant vigor
Toxicity
Keep this one strictly off the plate, no exceptions. Every part of a calla loads up on insoluble calcium oxalate crystals that drive sharp needles into any mouth that bites down, firing off instant burning, drooling, and swelling. That covers cats, dogs, horses, livestock, rabbits, birds, and people, and the sap can sting bare skin too, so scrub up after handling and park it well away from pets and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
A cat that bites any part feels the burn the instant it does, pawing at its mouth, drooling hard, and vomiting. The lips and tongue can swell and swallowing turns painful, so step in fast.
Dogs Toxic
A dog that chews the leaves or sap drools hard and gags, often sporting a swollen, sore mouth. Most bail out fast once the crystals sting, so they rarely eat enough to do lasting harm.
Horses Toxic
In a horse, the crystals scald the mouth and tongue, sparking swelling, drooling, and a flat refusal to eat. Horses cannot vomit, so the pain reads mostly as a sore mouth and feed left untouched.
Rabbits Toxic
The same calcium oxalate that hits cats and dogs fires up a rabbit's mouth and gut too. Keep callas, cuttings, and dropped leaves well out of reach of any rabbit grazing nearby.
Livestock Toxic
Cattle, sheep, and goats that graze the foliage pick up mouth and throat irritation, drooling, and an upset gut. The acrid taste usually scares them off, but hungry animals on thin pasture roll the dice anyway.
Birds Toxic
The leaves and sap pack the same irritating crystals for birds, so a pecking parrot or chicken can wind up with a sore, swollen mouth. Best move is to keep the plant away from birds entirely.
People Caution
No part of a calla is edible, and one bite fires off instant burning of the lips, tongue, and throat along with drooling and swelling. The sap alone can leave skin itchy and raw, so scrub up after handling and keep children well clear.
Keep plant, cut flowers, and sap away from pets and children; wash hands after handling as the sap can cause skin and mouth irritation.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Almost every calla you will chase down is a selection of the white arum lily, picked for the size or color of the spathe. These two pop up the most.
White Giant
White Giant goes big on oversized pure white spathes, claiming the showiest crown among the classic callas.
Green Goddess
Green Goddess opens white at the base and runs into green toward the tips, handing every bloom a bold two-tone look.
How to propagate
Callas multiply with ease, and splitting an established clump is hands down the fastest way to pump out more flowering plants.
DivisionEasy
Early spring or late summer to early fall · One growing season
Splitting a crowded clump is the quickest way to crank out more callas. Tackle it in early spring or in the cooler run from late summer into fall, lifting the rhizomes and breaking them apart by hand. Each healthy piece digs in and fills out over a single growing season.
SeedModerate
When ripe seed is available · Multiple seasons to flowering
Going the seed route asks for patience. Sow ripe seed whenever you can grab it, but the seedlings will spend several seasons sizing up before they bloom. Division blows past it if you just want more flowering plants in a hurry.
Bulbs & cormsEasy
Spring · One growing season
Kicking off from bought rhizomes is the go-to move. Plant them in spring, 3 to 4 inches deep and 12 to 18 inches apart, and they pile on growth and flower within their first season.
Myths
The calla lily is a true lily and causes fatal kidney failure in cats like Easter and tiger lilies do.
The name throws people off, but the calla is no true lily; it runs with the arum family. It does not trigger the deadly kidney failure that true lilies hit cats with. What it does carry is insoluble calcium oxalate crystals, which burn the mouth and set off drooling and vomiting in cats and dogs, painful for sure but rarely life-threatening.