Houseplant · Crassulaceae
Flaming Katy
Kalanchoe blossfeldiana
Hand it bright light, gritty soil, and dry spells between waterings, and this succulent gives back weeks of bloom.
Bright indirect
59–77°F · 15–25°C
USDA 10–12
6–12 in · 15–30 cm
Overview
Flaming katy is a little succulent from Madagascar that's grown for its long-lasting clusters of bright flowers. It's in the same family as jade and sedum, and just like them, it keeps water tucked away in thick, glossy leaves. That's handy, because it'll forgive a watering you forgot, though it'll rot in a hurry if you go the other way.
Most plants only get to about 6 to 12 inches (15 to 30 cm) tall, so it'll sit happily on a windowsill with room left over. The flowers show up in red, orange, pink, yellow, and white, and one good flush holds its color for weeks. Ever wonder why it pops up as a gift plant all year? Florists force it into bloom in every season.
Here's the good news: it's easy to keep going, and it's easy to get flowering again once you've got the trick down. It wants bright light and a run of long nights to set its buds, and it likes the soil bone dry before the next drink. Get those two right and it'll keep flowering for years.
Care
The short version: bright indirect light, gritty fast-draining soil, and a good soak only once the soil's dried out completely. Feed it lightly in the growing season, and give it long fall nights when you want it to flower again.
Light
Give it bright indirect light, like a spot by a sunny window that ducks the worst of the midday sun. It'll handle some direct sun and even partial sun, but skimp on light and it stretches out and gets shy about flowering.
Water
Let the soil dry completely between drinks, then soak it through and tip out whatever's pooled in the saucer. This is a succulent, so it rots fast in wet soil, which means when you're not sure, just wait. To get it flowering again, it also wants about six weeks of long nights, roughly 14 hours of uninterrupted darkness.
Soil
Pot 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 is its happy place, and that sharp drainage is really what keeps the roots from rotting.
Temperature
Normal room warmth does the trick, ideally 59°F to 77°F (15°C to 25°C). Keep it clear of cold drafts and frost, since it's a tender plant that won't put up with a chill.
Humidity
Plain household air is fine, and it's happiest on the low side of humidity. There's no number to worry about, and honestly, dry indoor air suits it better than a steamy bathroom would.
Feeding
Feed it monthly through spring and summer while it's growing, with a balanced water-soluble fertilizer cut to half strength. Back off in fall and winter once growth slows down.
Pruning
Snip off the spent blooms so it stays tidy, then pinch the stems back after flowering. That nudges it toward bushy, compact growth instead of a few long, bare stalks.
Repotting
Bump it up a pot size every 1 to 2 years, or sooner if it's crowded, and always grab one with drainage. Roots poking out the holes, water running straight through, or growth that's stalled all tell you it's time.
Size & spacing
You're looking at a compact plant about 6 to 12 inches (15 to 30 cm) tall with a spread of 8 to 16 inches (20 to 40 cm). Leave it enough room for air to move around the leaves, which helps keep powdery mildew away.
Troubleshooting
Just about every flaming katy problem comes back to water or light. Too much water and the roots rot, too little light and it goes leggy with barely a flower. Find what matches your plant below, and go after the cause, not just the look of it.
Soft, blackening stems and a base that's giving way
When the base turns soft and dark, that's root and crown rot, and it nearly always means there's been too much water in soil that won't drain. Want proof? Slip the plant out of its pot, and you'll find brown, mushy, smelly roots instead of firm pale ones. Cut every soft bit away with clean tools, pop it into fresh gritty mix, and keep it dry until it bounces back. From then on, a draining pot and a full dry-out between waterings is what stops it happening again.
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
Leggy, stretched-out stems and hardly any flowers
If it's leaning at the window with big gaps between its leaves, it just wants more light, and if it won't flower again, it's missing the long nights that get the buds going. So what fixes both? Pop it somewhere bright with indirect light, then hand it about six weeks of roughly 14 hours of complete darkness each night to kick off budding, and pinch those leggy stems back while you're at it. Keep it in good light all year with a controlled short-day stretch in fall, and the flowers keep coming.
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 white, powdery dusting on the leaves
See that pale, dusty stuff that wipes right off the leaves? That's powdery mildew, and it loves crowded plants stuck in still, damp air. Pull off the leaves that look worst, give everything more room so the air can move, and quit splashing the leaves when you water. Water down at the soil and keep the humidity low, and it won't get a foothold again.
Fix:
- Remove badly affected leaves
- Improve air circulation and spacing
- Avoid wetting the foliage when watering
Toxicity
This one needs care around animals. Every part of it holds bufadienolides, cardiac glycosides that upset the gut and, in bigger amounts, mess with the heartbeat. Keep it out of reach of pets and livestock, and ring a vet right away if an animal eats any of it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
If a cat nibbles any part, you'll usually see drooling, vomiting, and diarrhea before long. A bigger bite can mess with the heart rhythm, so treat that as urgent.
Dogs Toxic
Drooling, vomiting, diarrhea, and a dog that's gone flat are the usual giveaways. With a big mouthful, those same bufadienolides can slow or skip the heartbeat.
Horses Toxic
The cardiac glycosides are in every bit of the plant, so a horse that grazes on it risks colic, diarrhea, and a heart arrhythmia that's genuinely dangerous.
Rabbits Toxic
There's no safe amount for a rabbit, full stop. Even a couple of leaves can set off gut upset and the heart-rhythm trouble these glycosides are known for.
Livestock Toxic
Cattle, goats, and sheep that get into it can end up drooling, scouring, weak, and with an irregular heartbeat, all down to the bufadienolides.
Birds Toxic
Keep it well away from birds. The same cardiac toxin hits them too, and since they're so small, even a tiny bit does harm.
People Caution
Nobody should be eating this plant, and a mouthful can leave your stomach upset. Keep it away from small kids who might want to taste 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 you'll see these days has been bred for fuller flowers and a neat, compact shape. These two groups pretty much cover what's on the bench at the garden center.
Calandiva series
These ones stay compact and carry full, double, rose-like flowers in loads of different colors.
Flapjacks-flowered florist hybrids
These are the single-flowered florist types, and they pile on dense clusters of red, orange, pink, or yellow.
How to propagate
Flaming katy is easy to make more of, and one plant gives you plenty to start with. You can root a stem tip or grow whole new plants from a leaf, and both work best in spring or summer while it's actively growing.
Stem cuttingsEasy
Spring to summer during active growth · 2 to 3 weeks to root
Want the easy way to make more? Take a stem tip in spring or summer while it's growing. Snip a healthy tip, let the cut end callus for a day or two so it won't rot, then push it into gritty mix that's barely damp. Give it about 2 to 3 weeks and it'll root.
Leaf cuttingsModerate
Spring to summer · 3 to 6 weeks to form plantlets
A single leaf can do the job too, taken in spring or summer. Let the leaf callus, lay or sit it on well-drained mix, and keep it lightly moist while little plantlets pop up at the base over 3 to 6 weeks.
Myths
It's a harmless gift plant that's safe to have around pets.
Pretty as it is, this florist favorite really is toxic to cats and dogs. The bufadienolides in it are cardiac glycosides that bring on vomiting and diarrhea, and in enough quantity they can throw the heartbeat off. Think of it as a plant to keep up and out of reach, not a no-worries houseplant.