Stromanthe thalia ‘Tricolor’ — sold most often as ‘Triostar’ — has leaves that are difficult to describe without sounding like you’re exaggerating. The top surface is a mosaic of green, cream, and soft pink; the underside is a deep, saturated magenta that shows through whenever the leaves catch light or fold upward at night. It’s one of the most visually dramatic foliage plants in the Marantaceae family, which includes calathea and maranta. It is also one of the more specific plants in terms of what it needs to stay healthy. This guide covers the conditions that make or break it, and clears up the pet-safety question that has inconsistent answers across the internet.
| Stromanthe tricolor Quick Care Summary | |
|---|---|
| Light | Bright indirect light; no direct sun |
| Water | Every 5–7 days; keep soil evenly moist |
| Humidity | 60–80% |
| Temperature | 65–80°F (18–27°C) |
| Fertilizer | Monthly spring–summer, balanced liquid fertilizer |
What Makes Stromanthe Different From Calathea and Maranta?
All three are in the Marantaceae family and share some care similarities, but they’re distinct plants:
- Calathea: Large variety, most are grown for foliage patterns. Strict humidity requirements. Many species have been reclassified as Goeppertia.
- Maranta: Smaller, groundcover-habit. The original “prayer plant.” Slightly more forgiving with humidity.
- Stromanthe: Taller growth habit (can reach 3-4 feet). The ‘Tricolor’/’Triostar’ variety is uniquely variegated with pink tones not common in most Calatheas. The deep magenta underside is distinctive — visible when leaves fold at dusk.
- Ctenanthe: Often confused with Stromanthe. Similar striped patterns but without the pink. Usually listed separately at garden centers.
Why Does Stromanthe Move Its Leaves?
Stromanthe is a prayer plant — it follows nyctinasty, the movement of leaves in response to changes in light. During the day the leaves spread horizontally to maximize light capture. At dusk they fold upward, which is thought to reduce water loss and may have evolved to protect the leaf surface. The movement is driven by changes in turgor pressure in the pulvinus — a specialized joint at the base of each leaf.
The folded position at night shows off the magenta undersides of the ‘Tricolor’ variety, which is one of the plant’s most striking features. If the leaves stop folding at night, it’s usually a sign of insufficient light — the plant has less reason to track the sun cycle when light is already low.
Is Stromanthe Toxic to Cats and Dogs?
Stromanthe is not listed in the ASPCA toxic plants database — neither on the toxic list nor the non-toxic list. The plant simply hasn’t been catalogued. Many blogs state it’s “ASPCA-confirmed non-toxic” but there is no actual ASPCA page for Stromanthe to support that claim.
What is established: two of its closest relatives in the Marantaceae family — Calathea and Maranta leuconeura — are explicitly listed by the ASPCA as non-toxic to cats, dogs, and horses. Stromanthe shares the same family, genus group, and chemical profile. There are no documented reports of Stromanthe toxicity in pets in veterinary literature. The general expert consensus is that Stromanthe is not harmful to pets, but this is based on family-level inference rather than a specific ASPCA listing.
If you have pets and want maximum certainty, keep it out of reach until more formal documentation exists. If you want a formally ASPCA-confirmed safe option with similar care requirements, calathea is on the list.
How to Care for Stromanthe Tricolor
What Light Does Stromanthe Tricolor Need?
Bright indirect light — enough to support the variegation without scorching the leaves. This is one of the few Marantaceae plants that needs more light than a pure green-leafed calathea: the pink and cream variegated sections contain less chlorophyll, so the plant needs more light overall to photosynthesize adequately. A spot 2-3 feet from a bright east or west window is ideal. Avoid direct afternoon sun, which bleaches and scorches the variegated sections first.
In low light, the plant survives but loses pink coloration — new leaves emerge greener and less variegated. Move to a brighter spot to restore full coloration.
What Humidity Does Stromanthe Need?
60%+ relative humidity. This is the most common point of failure for stromanthe indoors. Standard household air (40-50%) keeps the plant alive but produces brown-tipped leaves consistently. A humidifier near the plant is the most reliable solution. A pebble tray adds a small benefit but rarely raises ambient humidity enough in a large room. Grouping with other high-humidity plants helps in contained spaces.
Misting directly on the leaves works short-term but also increases the risk of fungal leaf spots if water sits on the leaves. A humidifier is the better long-term approach.
How Often Should You Water Stromanthe?
Keep soil consistently moist but not waterlogged — allow the top inch to dry slightly between waterings, but never let it dry out completely. Stromanthe roots tolerate brief dryness less well than calathea roots; wilting (leaves losing their upright posture) is a sign it has been too dry for too long. Water when the top inch feels barely moist.
Use filtered water or water that has been left out for 24 hours. Stromanthe is sensitive to fluoride and chlorine, which accumulate in soil and cause brown leaf tips that look like humidity damage. If you’re using a humidifier but still getting brown tips, the water quality is the more likely culprit.
What Temperature Does Stromanthe Need?
65-85°F (18-29°C). Consistent warmth is important; cold drafts and sudden temperature drops cause the leaves to curl inward (curl is also the plant’s stress response to underwatering, so check both possibilities). Keep away from exterior doors in winter and air conditioning vents in summer.
What Soil Does Stromanthe Need?
Rich, moisture-retentive but well-draining mix. A blend of potting soil with 20-25% perlite and 10-15% coconut coir works well — the coir helps retain some moisture while perlite prevents waterlogging. Avoid cactus or succulent mixes that dry out too fast, and avoid dense garden soil.
How Often Should You Fertilize Stromanthe?
Monthly with a balanced liquid fertilizer at half strength during spring and summer. Reduce to every 6-8 weeks in autumn; stop fertilizing in winter when growth slows. Avoid fertilizing when the soil is dry — always water first. Fertilizer salt buildup from over-fertilizing shows as brown leaf edges.
How to Propagate Stromanthe
The most reliable method is division when repotting. Stromanthe spreads by rhizomes — underground stems that produce new growth points. When repotting in spring, separate clumps by gently pulling rhizome sections apart, ensuring each section has at least 2-3 growing points and a good portion of roots. Pot each section in fresh mix and keep humidity high until new growth emerges (typically 4-6 weeks).
Stem cuttings in water work with some success but are less reliable than division. Division is the standard method and produces established plants much faster.
Common Mistakes With Stromanthe Tricolor
Low humidity blamed on something else. Brown leaf tips are the most common complaint with stromanthe, and the cause is almost always low humidity or fluoride/chloride in tap water. Most care attempts (moving, watering differently, repotting) don’t address either cause. Add a humidifier and switch to filtered water before trying other fixes.
Treating it like calathea in low light. Standard calatheas tolerate lower light better than stromanthe tricolor because they have more chlorophyll. The variegated sections of ‘Tricolor’ need more light to compensate for reduced chlorophyll. A spot that works for a standard calathea may be too dim for stromanthe to maintain full variegation.
Overwatering in low light. In a dark spot, the plant uses water very slowly, so soil stays wet far longer. The combination of low light and regular watering creates root rot conditions. If you cannot put stromanthe in bright indirect light, reduce watering significantly.
Frequently Asked Questions
Why are my stromanthe leaves curling?
Leaf curl in stromanthe indicates either underwatering (the leaves curl inward along the midrib to reduce water loss) or cold temperature stress (curl in response to drafts or cold air). Check soil moisture first — if it’s dry, water immediately. If moisture is adequate, check for cold air sources near the plant.
Why is my stromanthe losing its pink color?
Pink and cream variegation in ‘Tricolor’ requires adequate light. In low light conditions, new leaves emerge greener as the plant prioritizes chlorophyll production over decorative patterning. Move to brighter indirect light and new leaves should show more pronounced variegation within 2-3 leaf cycles.
How big does stromanthe tricolor get indoors?
Typically 2-4 feet tall and 2-3 feet wide at maturity in indoor conditions. It grows faster than calathea, producing new leaves regularly in the growing season. Occasional pruning of old, damaged leaves keeps the plant tidy.
Is stromanthe the same as calathea?
No. Both are in the Marantaceae family and have similar care requirements, but they’re different genera. Stromanthe is recognizable by its taller, more upright growth habit and — in the ‘Tricolor’ variety — the distinctive combination of pink variegation on top and deep magenta undersides. Most calatheas have contrasting leaf patterns but not pink variegation in the same way.