Bulb · Araceae
Caladium
Caladium bicolor
Supply warm soil, dappled shade, and steady moisture, and the caladium answers with heart-shaped leaves marbled in red, pink, and white.
Partial shade
Every 2–4 days
61–86°F · 16–30°C
60–90 days
Overview
Caladiums earn their place on foliage alone, not bloom. Each tuber drives up large, paper-thin, heart-shaped leaves marbled in red, pink, white, and green, and one plant can carry color into a shaded corner where few others perform. As a member of the arum family, alongside philodendrons and peace lilies, it inherits that group's appetite for warmth and humidity.
Being a tropical tuber, it runs entirely on heat. It breaks dormancy, grows quickly, and reaches full size in a single season before dying back to rest as temperatures drop. It works in a shaded bed, a patio container, or indoors as a houseplant, but in each setting it demands warm soil and air at roughly 16°C and above before it will move at all.
Color is the point of the plant, and shade is what protects it. Strong light pushes the leaf to lay down more chlorophyll, which masks the bright markings toward plain green while also scorching the delicate blades, whereas dappled light holds the patterning. A caladium is undemanding once the warmth arrives, but exacting about that single requirement.
Care
The short version: give it partial to dappled shade, soil kept warm rather than cold, and even moisture across the growing season. Feed sparingly, hold the humidity high, and taper the water as the leaves yellow into dormancy.
Light
Partial to dappled shade is the target, allowing perhaps 2 to 4 hours of soft sun while screening out hot afternoon light. Excess direct sun drives the leaf to mask its bright markings under chlorophyll and scorches the thin blades, whereas richer shade keeps the color at its deepest.
Water
An active caladium drinks heavily, so hold the soil evenly moist to the touch without letting it waterlog, since standing water suffocates and rots the tubers. Watering every 2 to 4 days fits most plants, and you scale back steadily as the leaves yellow toward dormancy.
Soil
Use fertile, well-drained soil rich in organic matter, which lets it retain moisture while shedding excess so the medium never stays wet. A slightly acidic pH of 5.5 to 6.0 suits the plant, and free drainage is the single best defense against tuber rot.
Temperature
Heat governs everything with this plant. Caladiums perform between 61°F and 86°F (16°C to 30°C) and stall in anything cooler because the tuber cannot mobilize its reserves, so wait for the soil to warm before planting out.
Humidity
As tropical plants they expect humidity of 60% or more. Dry indoor air pulls moisture from the thin blades faster than the roots replace it, crisping the edges brown, so cluster plants together, stand them on a pebble tray, or run a humidifier in a dry room.
Feeding
Feed every two weeks through the growing season with a balanced liquid fertilizer, or substitute a slow-release low-phosphorus formula. Keep it light, since overfeeding pushes the reds and whites toward plain green.
Pruning
Little pruning is needed. Cut yellowing or damaged leaves off at the base, and removing the central bud from a tuber before planting redirects its energy into a greater number of shoots and leaves.
Repotting
Caladiums are lifted and replanted each year from stored tubers rather than potted up. Leave settled clumps alone, lifting and dividing only when the tubers crowd and lift at the surface or the leaves dwindle across the season.
Size & spacing
Expect a caladium to reach 12 to 30 inches (30 to 76 cm) tall with an equal spread. Space tubers 8 to 12 inches apart so the broad leaves can fill in without jostling one another.
When to plant
Caladiums answer to soil warmth rather than the date. Start tubers indoors a few weeks ahead of the last frost for an earlier start, then transplant only after the ground has warmed through in late spring. They bulk up over summer and retreat into dormancy as the season cools.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Start tubers indoors 4-6 weeks before the last frost in a warm spot, keeping the medium about 70 degrees F, to get a head start in cold-winter regions
- Plant: After all danger of frost has passed and soil reaches at least 60-70 degrees F (late spring to early summer)
- Harvest: Grown for foliage, which reaches full size in one season; insignificant arum-type spathe flowers may appear in summer
Hardiness
USDA hardiness zones: 9–10
Temperature: down to -7°C
Troubleshooting
Two areas account for most caladium problems: tubers that stay dormant in cold ground, and leaves that lose their patterning or get grazed. Catch the early signals and most of it is straightforward to prevent. Match the symptom below, then act while there is still season left.
Tubers stall and decay underground rather than breaking dormancy
Cold, wet ground is the usual culprit when a caladium tuber refuses to sprout and breaks down instead. Tropical tubers need warmth to mobilize stored reserves, so hold off planting until the soil settles at a steady 60°F to 70°F (16°C to 21°C), open up the drainage so moisture moves through rather than pooling, and discard any tuber that already gives under a squeeze. Sourcing clean, disease-free stock is the surest way to keep fungal tuber rot out of the bed from the start.
Fix:
- Wait to plant until soil is consistently 60-70 degrees F
- Improve drainage and reduce watering so soil is moist but not saturated
- Discard soft or rotted tubers and start with disease-free stock
Markings drain to plain green, losing their red, pink, and white
When the patterning dulls toward uniform green, the cause is almost always excess direct sun or heavy feeding. Bright light drives the leaf to build more chlorophyll, which masks the red, pink, and white pigments, so shift the plant into partial or dappled shade out of harsh afternoon light, and limit feeding to a light dose once or twice per season. Shade is what preserves the pigment, and the deeper the dapple, the more striking the leaves stay.
Fix:
- Move to partial or dappled shade with protection from hot afternoon sun
- Reduce fertilizer to a light application once or twice in the season
Chewed margins and irregular holes punched through the foliage
Foliage eaten into ragged holes is nearly always down to slugs and snails, soft-bodied feeders that work after dark and betray themselves with glistening slime trails. Collect them by hand at night or set bait, and strip out the cool, damp refuges where they wait out the day. Leaves that are torn rather than neatly grazed signal wind or hail punishing the brittle blades instead, so a sheltered position spares them.
Fix:
- Hand-pick slugs and snails or use baits per label
- Site out of strong wind to protect brittle leaves
Toxicity
The whole plant is toxic, leaf, stem, and tuber alike, without exception. Every part is loaded with insoluble calcium oxalate crystals that behave like microscopic needles, so one bite drives intense burning, drooling, and swelling through the mouth and throat. Nothing on the plant is edible, so keep it and any stored tubers clear of pets, livestock, and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
A single bite fires the raphides into the soft tissue at once, and the cat paws frantically at its mouth and drools heavily. Expect the lips, tongue, and throat to swell, with vomiting and laboured swallowing close behind.
Dogs Toxic
Any chewed part stings a dog's mouth instantly, triggering thick drool and a swelling tongue. Most spit it out quickly, though vomiting and a lost appetite can drag on for the better part of a day.
Horses Toxic
On contact the crystals inflame the lips and mouth, leaving a horse in pain, drooling, and struggling to swallow. Because horses cannot vomit, the irritation stays confined to the tissue that touched the plant.
Rabbits Toxic
The same needle-like crystals scald a rabbit's mouth and gut and quickly drive it off its food. Keep both the growing plant and any dormant tubers well beyond its reach.
Livestock Toxic
Goats, sheep, and cattle that sample the leaves get an immediate burn to the mouth and gut. The sting is sharp enough that most reject it on the spot, but fence the plants away from pasture all the same.
Birds Toxic
Oxalate raphides irritate a bird's mouth and crop exactly as they do in mammals, so pet birds must never reach the leaves or the sap.
People Caution
No part is fit to eat. A bite sets the lips and mouth burning at once, with drooling and swelling, and the sap can leave skin itchy, so wash up after handling and keep the plant clear of children.
Keep plants and stored tubers out of reach of pets and children; wash hands after handling sap.
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
Hundreds of named caladiums exist, grouped chiefly by leaf shape. A handful stand out as the selections worth knowing first.
Candidum
A long-standing fancy-leaved selection valued for near-white leaves traced through with strong green veining.
Pink Cloud
A named fancy-leaved cultivar in the NC State listing, marked by gentle pink-flushed foliage.
Lance-leaved (strap-leaved) types
Narrower in habit and usually under 12 inches tall, these tolerate more sun than the fancy-leaved forms.
How to propagate
Caladiums increase through their tubers, whether you cut a tuber into sections or detach the offsets a clump produces on its own.
DivisionEasy
Late winter to early spring before planting, while tubers are dormant · 4-6 weeks to sprout in warm soil; full size in one season
Divide dormant tubers in late winter or early spring. Slice a large tuber into sections, making sure each keeps at least one eye, then leave the cut surfaces to dry and callus, which seals them against rot before they go in. Set each piece eye-side up about 2 inches deep; in warm soil it breaks ground in 4 to 6 weeks and reaches full size within the one season.
Offsets & pupsEasy
At lifting in autumn or replanting in spring · One growing season to reach mature size
A parent tuber forms its own daughter tubers around the crown as it grows. Lift the clump when it goes dormant in autumn, or as you replant in spring, ease the offsets away from the parent, and grow each one separately, where it needs a single growing season to size up.
Myths
Bright leaf color depends on giving caladiums full sun.
The reverse holds true. Pigment runs deepest under partial or dappled shade, whereas too much direct sun fades the reds, pinks, and whites toward green as the leaf builds chlorophyll, and the same light scorches the thin blades.
Caladium tubers go in early spring along with the hardy bulbs.
Being tropical, caladiums stall or rot in cool ground rather than rooting. Wait until the soil reaches at least 60°F to 70°F (16°C to 21°C) before setting the tubers, which in practice means late spring rather than the first mild stretch.