Houseplant · Crassulaceae
Flaming Katy
Kalanchoe blossfeldiana
Give it bright light, gritty soil, and dry spells between waterings, and its thick leaves carry weeks of bright bloom.
Bright indirect
59–77°F · 15–25°C
USDA 10–12
6–12 in · 15–30 cm
Overview
Flaming katy is a small succulent from Madagascar, grown for the tight clusters of bright flowers that crown its stems. It belongs to the same family as jade and sedum, and shares their thick, glossy leaves that feel firm and water-filled between the fingers. Those plump leaves hold a reserve that carries it through a missed watering, while soggy soil softens and rots them fast.
The whole plant stays low, just 6 to 12 inches (15 to 30 cm) tall, a rounded mound of fleshy foliage. From it rise stems topped with bloom in red, orange, pink, yellow, and white, the small flowers packed close so the color reads as a solid patch, and a single flush holds that color for weeks. Florists time the bloom so it turns up in flower in any season.
Up close its character is all plump leaves and dense flower heads, and the plant is as easy to flower again as it is to keep. It needs bright light and a stretch of long nights to set the buds that open into those clusters, and its soil should dry out completely between waterings. Meet both and the bright heads return year after year.
Care
The short version: bright indirect light, gritty fast-draining soil, and a thorough soak only once the soil has dried out completely. Feed lightly in the growing season, and give it long fall nights to set fresh flower buds.
Light
Give it bright indirect light, such as a spot near a sunny window out of the harshest midday rays, and the leaves stay tight and well colored. It takes some direct sun and even partial sun, but in too little light the stems stretch long and bare and the flower heads thin out.
Water
Let the soil dry out completely between waterings, then soak it through and tip out whatever pools in the saucer. The fleshy leaves already hold a water store, so this succulent softens and rots fast in soggy soil, and waiting is the safer call. To set fresh buds it also needs about six weeks of long nights, roughly 14 hours of uninterrupted darkness.
Soil
Plant it in a gritty, well-drained mix that water runs straight through, like a cactus blend. A slightly acidic pH of 6.0 to 6.5 suits it, and the sharp drainage is what keeps the pale roots firm rather than rotting.
Temperature
Ordinary room warmth keeps the leaves plump and sound, ideally 59°F to 77°F (15°C to 25°C). Keep it clear of cold drafts and frost, since this tender plant will not take a chill.
Humidity
Average household air is plenty, and it sits happiest on the low side of humidity. There is no number to chase, and the dry air of an ordinary room suits its fleshy leaves better than a steamy bathroom.
Feeding
Feed it monthly through spring and summer while it is in growth, with a balanced water-soluble fertilizer diluted to half strength. Ease off in fall and winter as the new leaves slow.
Pruning
Snip off the spent flower heads to keep it neat, then pinch the stems back after flowering. That pushes out bushy, leaf-packed growth instead of a few long, bare stalks.
Repotting
Move it up a pot size every 1 to 2 years, or sooner if it crowds, always into a container with drainage. Roots poking from the holes, water running straight through, or stalled growth all show it is time.
Size & spacing
Expect a compact mound of 6 to 12 inches (15 to 30 cm) tall with a spread of 8 to 16 inches (20 to 40 cm) of fleshy foliage. Leave room for air to move between the leaves, which keeps the chalky film of powdery mildew off them.
Troubleshooting
Almost every flaming katy problem leaves a visible mark, and it traces back to water or light. Too much water turns the firm roots brown and soft, while too little light stretches the stems long and bare with few flower heads. Match what you see on the plant below and treat the cause behind it.
Stems turning soft and black at the base
When the lower stems lose their firmness and darken to black at the base, root and crown rot has set in, the result of too much water held in soil that will not drain. Slide the plant from its pot and the roots tell it plainly: brown, soft, and foul-smelling where they should be firm and pale. Every soft, discolored piece comes away with clean tools, the plant goes into fresh gritty mix, and the soil stays dry until it firms up again. A draining pot and a complete dry spell between waterings keep the base solid.
Fix:
- Remove the plant from wet soil
- Cut away all rotted tissue with clean tools
- Repot into fresh gritty, well-drained mix
- Withhold water until the plant recovers
Long, bare stems leaning with no blooms
Stems that stretch long and bare, leaning toward the window with wide gaps opening between the leaves, are starved of light, and when no flower clusters appear the plant has missed the long nights that set its buds. Brighter indirect light pulls the new growth back tight. About six weeks of roughly 14 hours of complete darkness each night brings the buds on, and the stretched stems can be pinched back so fresh shoots fill in. Steady bright light through the year with a controlled short-day spell in fall keeps the flowers forming.
Fix:
- Move to a bright spot with indirect light
- Provide about six weeks of roughly 14 hours of complete darkness each night to trigger budding
- Pinch back leggy stems
A chalky white film dusting the leaves
Pale spots and a chalky white film spreading over the glossy leaves are powdery mildew, a coating that lifts away under a fingertip and takes hold where crowded plants sit in still, humid air. The worst-coated leaves come off first. Wider spacing lets air slip between the foliage, and keeping water off the leaf surfaces denies the film a foothold. Watering down at the soil and holding the air dry keeps the leaves clean.
Fix:
- Remove badly affected leaves
- Improve air circulation and spacing
- Avoid wetting the foliage when watering
Toxicity
For all its plump leaves and bright bloom, this plant is a real hazard to animals. Every part holds bufadienolides, cardiac glycosides that upset the gut and, in larger amounts, disturb the heartbeat. Keep it out of reach of pets and livestock, and call a vet right away if an animal eats any of it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
A cat that bites into the fleshy leaves soon drools, vomits, and has diarrhea. A larger mouthful can disturb the heart rhythm, so treat it as urgent.
Dogs Toxic
A dog shows drooling, vomiting, diarrhea, and flagging energy after chewing any part. With a large helping, the same bufadienolides can slow or skip the heartbeat.
Horses Toxic
The cardiac glycosides sit in every part, from the thick leaves to the flower stems, so a grazing horse risks colic, diarrhea, and a dangerous heart arrhythmia.
Rabbits Toxic
No amount of the succulent leaves is safe for a rabbit. Even a few can bring on gut upset and the heart-rhythm trouble these glycosides cause.
Livestock Toxic
Cattle, goats, and sheep that browse it can suffer drooling, scouring, weakness, and an irregular heartbeat from the bufadienolides.
Birds Toxic
Keep it well clear of birds. The same cardiac toxin reaches them, and their small size means even a little does harm.
People Caution
No part of this plant is meant to be eaten, and swallowing it can upset the stomach. Keep it away from small children drawn to the bright flowers.
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
Most flaming katy sold today has been bred for fuller flower heads and a tight, compact mound of leaves. These two groups cover the forms you will see at the garden center.
Calandiva series
Each compact plant carries fully double flowers that swirl open like small roses, set across a wide span of colors.
Flapjacks-flowered florist hybrids
These single-flowered florist forms mass their blooms into dense clusters of red, orange, pink, or yellow.
How to propagate
Flaming katy makes new plants from its own pieces with ease, and one plant offers plenty to start from. A snipped stem tip will root, and a single thick leaf will raise plantlets, both best taken in spring or summer while the plant is growing.
Stem cuttingsEasy
Spring to summer during active growth · 2 to 3 weeks to root
A stem tip, snipped in spring or summer while the plant is growing, is the easiest piece to start from. The cut end is left to dry into a firm callus over a day or two so it will not rot, then pressed into gritty, barely moist mix. Fine new roots push out in about 2 to 3 weeks.
Leaf cuttingsModerate
Spring to summer · 3 to 6 weeks to form plantlets
A single thick leaf, taken in spring or summer, can raise new plants of its own. The leaf is callused, then laid or stood on well-drained mix and kept lightly moist while tiny plantlets bud out along its base over 3 to 6 weeks.
Myths
It is a harmless gift plant that is safe around pets.
Behind the bright clusters of flowers, this florist plant is toxic to cats and dogs. Its bufadienolides are cardiac glycosides that bring on vomiting and diarrhea and, in quantity, can throw off the heartbeat. The colorful blooms are exactly what draws a curious animal, so keep it well out of reach.