Houseplant · Marantaceae
Stromanthe Triostar
Stromanthe thalia 'Triostar'
Keep the water soft, the air humid, and the sun off it, and this tricolor prayer plant stays gorgeous.
Bright indirect
USDA 10–12
2–5 ft · 0.6–1.5 m
Overview
Stromanthe Triostar is all about the leaves, streaked with green, cream, white, and pink and flipped over to a deep burgundy underneath. It's a prayer plant, so here's a fun quirk: the leaves lift up at night and drop back down by morning. The color is really the whole reason to grow it, and it keeps that color when you give it what it wants.
Is it a bit fussy? Sure, but there's a logic to it. It comes from the warm, humid forest floor of Brazil, so it just wants that same steady warmth and moisture indoors. A few things set it off, like the minerals in tap water, dry air, and harsh direct sun, but catch those early and it stays lush and happy.
Give it good conditions and it grows into a tidy clump of upright stems you can split every year or two. Get the water, light, and humidity dialed in and each new leaf opens up in that same bold tricolor. Not bad for a little effort, right?
Care
The short version: bright indirect light and no direct sun, soft filtered water, and soil that stays evenly moist. Keep humidity above 60%, keep it warm, and feed it lightly while it's growing.
Light
It loves bright indirect light, like the kind you get near an east or north window. Too much direct sun and the pale pink and cream will bleach and scorch, but too much shade and the color goes flat, so aim for dappled light or pop a sheer curtain in the window.
Water
Keep the soil evenly moist but not soggy, watering more when it's actively growing and backing off in winter. Here's the catch, though: fluoride, chlorine, and salts in tap water will burn the leaf edges, so it's worth using filtered, distilled, or rainwater instead.
Soil
Go with a rich, organic mix that holds some moisture but still drains, because it doesn't like drying out and it hates sitting in water either. It's easygoing about pH, so anywhere from 6.0 to 8.0 is fine.
Temperature
Keep it cozy, and don't let it get colder than about 59°F (15°C). It's a tropical plant, so cold drafts are a no, which means keeping it clear of chilly windows and doorways once winter rolls in.
Humidity
This is where a lot of people slip up. It really wants humidity of 60% or more, and dry indoor air is usually why the leaf edges go brown. A humidifier, a pebble tray, or just grouping a few plants together will all help keep things moist.
Feeding
Feed it lightly through the spring and summer growing season, roughly every 2 to 3 weeks. A low-nitrogen liquid fertilizer does the job, and you can skip feeding in the cold months when it slows down anyway.
Pruning
Honestly, there's not much to prune. Just trim off any tired or damaged leaves at the base when you see them, and the clump stays looking sharp.
Repotting
Plan to repot every 1 to 2 years in spring, once roots start circling the pot, water runs straight through, or the clump looks packed. Since it's already out of the pot, that's the easy moment to divide it too.
Size & spacing
Indoors it'll form an upright clump about 2 to 5 feet (60 to 150 cm) tall and 2 to 3 feet (60 to 90 cm) wide. Give it a bit of elbow room on the shelf so air can move around the leaves and nothing gets squished.
Troubleshooting
Most of the time, trouble with this plant shows up on the leaves, and it usually comes down to water, air, or light. Take a look at the edges, the variegation, and the soil, and you can usually spot a problem while it's still small. Find what matches below, then go after the cause instead of just the symptom.
A droopy plant with mushy stems and sour-smelling soil
Soggy, airless soil leads to root and stem rot, and that sour smell is the dead giveaway. Pop the plant out, cut away every soft, brown root and stem, and repot into fresh, well-draining mix. After that, water just enough to keep things evenly moist and make sure the pot can actually drain.
Fix:
- Unpot and remove all soft, rotten roots and stems
- Repot into fresh, well-draining mix
- Water only to keep evenly moist, never soggy, and ensure drainage
Fine webbing and a speckly, dusty look on the leaves
Hot, dry air pretty much rolls out the welcome mat for spider mites, which hang out on the undersides and joints and leave a dusty, stippled mess. Give the foliage a rinse, wipe the undersides, and raise the humidity to push them back. Then treat with insecticidal soap or horticultural oil and repeat whenever the label says.
Fix:
- Rinse foliage and wipe undersides
- Raise humidity, which discourages mites
- Treat with insecticidal soap or horticultural oil and repeat per label
White cottony fuzz hiding in the leaf joints
Those fluffy white clumps are mealybugs, and they often leave a sticky mess behind. Dab each one with a cotton swab dipped in isopropyl alcohol, then follow up with insecticidal soap or horticultural oil. Keep the plant off on its own and treat it again, because a few leftovers will bring the whole colony back.
Fix:
- Dab insects with isopropyl-alcohol-moistened swab
- Treat with insecticidal soap or horticultural oil
- Isolate the plant and repeat treatments
Brown, crunchy edges showing up on the leaves
This one's picky about water, and that's usually what's going on here. The fluoride, chlorine, and salts in tap water pile up in the leaf and burn the edges and tips, while the middle stays nice and green. Switch to filtered, distilled, or rainwater, bump the humidity past 60%, and don't let the soil dry out, because dry air and dry roots just make it worse.
Fix:
- Switch to filtered, distilled, or rainwater
- Raise humidity to 60%+ with a humidifier or pebble tray
- Keep soil consistently moist, never bone-dry
- Trim badly browned edges for appearance only
Pale, scorched patches on the cream and pink bits
Those bright cream and pink areas barely have any chlorophyll, so direct sun burns them first. Keep an eye out for pale, crispy spots on the leaves sitting in the midday sun. Just move it to bright indirect light or an east or north window, and if the sun's still strong, a sheer curtain softens it right up.
Fix:
- Move to bright indirect light or an east/north-facing aspect
- Filter harsh direct sun with a sheer curtain
Toxicity
Good news if you've got pets: this is a non-toxic prayer plant, and there's no poison on record in its leaves or stems. NC State Extension calls the species pet friendly, so if a cat, dog, or rabbit sneaks a nibble, it's really no big deal. It's not something you'd eat, and a big mouthful of leaf might cause a quick stomach ache from the fibre, but nothing here is actually dangerous.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are totally fine with it. NC State tags this prayer plant as pet friendly and there's no known toxin, so a curious nibble isn't anything to stress about.
Dogs None
Dogs are all good around it too. Nothing in the leaves is poisonous, though a dog that scarfs down any houseplant might get a quick tummy ache from the fibre.
Horses Safe
There's no toxicity on record for horses. It lives indoors, not out in a paddock, so they won't really cross paths, and a stray leaf wouldn't hurt anyway.
Rabbits Safe
Rabbits can hang around it no problem. The leaves don't carry any toxin, so a sneaky bite won't do them any harm.
Livestock Safe
Nothing in this plant is toxic to grazing animals, and since it's a houseplant, it hardly ever ends up near them.
Birds Safe
Pet birds are safe next to it. There's no harmful compound in the leaves or stems to worry about.
People Safe
It's safe to keep in any room. You wouldn't eat it, of course, but there's no toxin in it, so kids are perfectly fine around it.
As with any houseplant, discourage pets from chewing foliage; ingestion of plant fibre can still cause mild, transient GI upset
Varieties
Triostar is the one everybody recognizes, but it's not the only painted-leaf Stromanthe out there. Here are the two you'll want to tell apart.
'Triostar' (syn. 'Tricolor')
You'll spot green leaves streaked with white, cream, and pink up top, and a solid pink to burgundy on the flip side.
'Magic Star'
This one skips the pink and goes for creamy white speckles on green leaves, with deep maroon undersides to match.
How to propagate
Want more of these? There's basically one good way to do it, and it happens to line up with repotting a crowded clump.
DivisionModerate
Spring, before new growth starts · Several weeks to a few months
The easiest way to make more is to split the rhizome clump in spring, right before it starts pushing new growth. Pot up each piece and keep it warm, humid, and evenly moist while it settles in. Just be patient, because a division can take several weeks to a few months to root in and really get going.
Myths
Stromanthe Triostar is basically just a Calathea, right?
You'll often see it sold, and even labeled, as 'Calathea Triostar', but it's actually its own genus, Stromanthe. The accepted name is Stromanthe thalia, with Stromanthe sanguinea as a synonym, which is why the RHS lists it as Stromanthe sanguinea 'Triostar'.