Bulb · Araceae
Calla Lily
Zantedeschia aethiopica
Hand it rich, damp soil and a sunny spot, and your calla will thank you with tall, graceful blooms.
Full sun
Every 2–4 days
USDA 8–10
2–3 ft · 0.6–1 m
Overview
Few flowers feel as effortlessly elegant as the calla, with its single curled spathe folded around a slim golden spike. Here is a happy surprise for anyone who finds the name confusing: it is not a true lily but one of the arum family, hailing from southern Africa and welcomed in gardens everywhere for its cut stems and its strong summer color. White is the classic, yet relatives arrive in soft cream, sunny yellow, and rich wine tones, so there is plenty to fall for.
Each plant rises from a plump underground rhizome and returns faithfully season after season where winters stay mild. If overwatering usually keeps you up at night, you can relax here, because this is a plant that genuinely loves wet feet. It is content in soggy ground or beside a pond and will stand in water up to about a foot deep without sulking, so during active growth the usual fear of giving too much barely applies.
As lovely as the calla is, please remember the whole plant is toxic to people and animals. Sharp calcium oxalate crystals run through every part and sting the mouth the moment they are bitten, so this is a flower to enjoy with your eyes, not your taste buds. Tuck it somewhere curious pets and small hands cannot reach the leaves or the sap, and you and the plant will both be just fine.
Care
The short version: give it full sun to part shade, keep the soil rich and steadily moist, offer a balanced feed through the growing months, and lift and divide the rhizomes every year or two once the clump fills out.
Light
Your calla blooms its best in full sun, yet it copes kindly with partial shade too, which is a real comfort where summer afternoons turn fierce. The brighter its spot, the sturdier and more upright those flowers will stand.
Water
This is one plant you truly cannot overdo. Keep the soil consistently moist to boggy, watering every 2 to 4 days while it grows, and simply never let it dry out. It will even sit in standing water up to about a foot deep, so leaning toward damp is exactly right.
Soil
Settle it into rich, humusy clay or loam brimming with organic matter, and it will feel right at home. Unlike fussier bulbs, the calla forgives poor drainage and the occasional flood, and it is easygoing about pH anywhere from 6.0 to 8.0.
Temperature
It takes a wide span in stride, roughly 10°F to 86°F (-12°C to 30°C), though it is happiest in gentle summer warmth. Hard freezes simply send it into dormancy, so where winters bite you can lift the rhizomes or cover them with a thick blanket of mulch.
Humidity
Calla lilies enjoy air on the humid side, which suits a plant so fond of damp ground and pond edges. Do not fret over dry air on its own, because as long as the soil stays moist the plant stays content.
Feeding
Offer a meal monthly through spring and summer while it is growing hard, reaching for a balanced general-purpose fertilizer. As the leaves begin to fade and the plant eases toward rest, you can let the feeding taper off.
Pruning
Snip away spent flower stalks and any leaves turning yellow or brown to keep the clump looking fresh. When the foliage dies back for the year, trim it down as the plant settles into its winter rest.
Repotting
Plan to divide and repot every 1 to 2 years, or a little sooner if the clump starts crowding itself. Rhizomes packed into the pot, fewer blooms than before, and roots peeking from the drainage holes are all friendly hints that it is time.
Size & spacing
A grown calla reaches about 2 to 3 feet (61 to 99 cm) tall and spreads 12 to 24 inches (30 to 61 cm) across. Space the rhizomes around 12 to 18 inches (30 to 46 cm) apart so every clump has the elbow room to fill in nicely.
When to plant
Callas take their cue from rising warmth, so there is no rush in early spring. If your winters turn cold, start the rhizomes indoors in late winter and move them outside once the last frost has gone. Flowers arrive in early summer, and the display is at its loveliest right 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 worries begin down in the soil or show on the leaves, and the good news is that nearly all of them are fixable. Rot from waterlogged ground is the one to keep an eye on, while beetles and thrips tend to be more of a bother than a real danger. Find your symptom below and act early, and you will rarely lose a plant.
Soft, mushy rhizome and collapsing leaves
If the rhizome turns soft and the foliage flops and caves in, you are looking at rhizome rot, which sets in when soil stays soggy and airless for too long. Gently lift the rhizome and have a look: any brown, mushy, bad-smelling tissue needs to come out. Trim the soft patches from a rhizome still worth keeping, let the cuts dry and heal, then tuck it back into ground that drains more freely, and it has a good chance of bouncing back.
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 nibbled down to lace and blooms left ragged point to Japanese beetles, those metallic green-bronze visitors that descend on foliage and flowers all summer. The easiest answer is to pick them off by hand and drop them into a tub of soapy water. On a plant that is hard hit, keep at it daily, since every beetle you take early means fewer arriving 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, usually means tiny banded greenhouse thrips are rasping away at the surface. Pinch off and bin the worst-affected foliage to ease the load. Then just keep your calla well fed and watered, because a strong, vigorous plant shrugs off light thrips damage with ease.
Fix:
- Remove and dispose of heavily infested foliage
- Improve growing conditions to support plant vigor
Toxicity
Think of every calla as strictly for looking at, never for eating. Each part holds insoluble calcium oxalate crystals that press tiny needles into any mouth that bites down, bringing fast burning, drooling, and swelling. That goes for cats, dogs, horses, livestock, rabbits, birds, and people alike, and even the sap can leave bare skin sore, so a quick hand-wash after handling and a safe spot away from pets and children keeps everyone comfortable.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
A cat that bites any part will feel the sting at once, pawing at its mouth, drooling heavily, and often vomiting. The lips and tongue may swell, and swallowing becomes painful, so step in gently and call your vet if you are worried.
Dogs Toxic
A dog that chews the leaves or sap usually drools hard and gags, sometimes with a swollen, tender mouth. Most pull away quickly once the crystals sting, so they seldom eat enough to come to any lasting harm.
Horses Toxic
In a horse, the crystals scald the mouth and tongue, leading to swelling, drooling, and a clear wish to stop eating. Since horses cannot vomit, the trouble shows mainly as a sore mouth and a refusal of feed.
Rabbits Toxic
The same calcium oxalate that bothers cats and dogs will irritate a rabbit's mouth and gut just as much. Keep your callas, any cuttings, and dropped leaves well out of reach of any rabbit grazing nearby.
Livestock Toxic
Cattle, sheep, and goats that graze the foliage can end up with a sore mouth and throat, drooling, and an upset stomach. The harsh taste usually warns them off, though a hungry animal on poor pasture may still take a bite.
Birds Toxic
Birds meet the very same irritating crystals in the leaves and sap, so a curious parrot or chicken can finish up with a sore, swollen mouth. The kindest choice is simply to keep the plant away from birds altogether.
People Caution
No part of a calla is safe to eat, and a single bite brings instant burning of the lips, tongue, and throat along with drooling and swelling. Even the sap can leave skin itchy and raw, so wash up after handling and keep children at a safe distance.
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
Nearly all the callas you will come across are selections of the white arum lily, picked for the size or shade of the spathe. These two are the ones you are most likely to spot.
White Giant
Loved for its oversized, pure white spathes, White Giant is the boldest and most eye-catching of the classic callas.
Green Goddess
Green Goddess opens white near the base and softens into green at the tips, so each bloom carries a gentle two-tone look.
How to propagate
Making more callas is wonderfully simple, and lifting and splitting a settled clump is the quickest path to a whole new batch of flowering plants.
DivisionEasy
Early spring or late summer to early fall · One growing season
The friendliest way to grow your collection is to split a crowded clump. Choose early spring or the cooler stretch from late summer into fall, lift the rhizomes, and ease them apart with your hands. Each healthy piece will settle in and fill out over one growing season, so patience is barely needed.
SeedModerate
When ripe seed is available · Multiple seasons to flowering
Raising callas from seed asks a little more patience from you. Sow ripe seed whenever you can gather it, but know the seedlings will spend several seasons growing up before they flower. If you simply want more blooming plants soon, division is the far quicker and kinder route.
Bulbs & cormsEasy
Spring · One growing season
Starting with bought rhizomes is the path most growers take, and it is reassuringly straightforward. Plant them in spring, 3 to 4 inches deep and 12 to 18 inches apart, and they will put on growth and reward you with flowers in that very first season.
Myths
The calla lily is a true lily and causes fatal kidney failure in cats like Easter and tiger lilies do.
It is an easy mix-up, but the calla is not a true lily; it belongs to the arum family instead. That means it does not cause the deadly kidney failure that real lilies bring on in cats, so you can set that particular fear aside. What it does hold are insoluble calcium oxalate crystals, which burn the mouth and prompt drooling and vomiting in cats and dogs, uncomfortable for sure but rarely life-threatening.