Stromanthe sanguinea "Triostar" is a showy tropical plant valued for the vividly colored leaves in shades of green, red and creamy white. Suitable for planting outdoors in the warm climates of U.S. Department of Agriculture Plant Hardiness Zones 9b to 10, Stromanthe sanguinea "Triostar" is grown indoors in cooler climates.
Stromanthe grown indoors needs a well-drained, commercial potting medium. Any good quality, lightweight, potting medium is fine, but a handful of coarse sand or perlite improves drainage. Outdoors, stromanthe prefers rich, moist soil, but it must drain well, as stromanthe is prone to rot in wet soil, especially during the winter.
Water and Humidity
Indoors or out, stromanthe needs consistently moist soil. Water the plant regularly, using lukewarm water, whenever the top of the soil feels slightly dry. Never allow the soil to become either sopping wet or completely dry. Indoors, Stromanthe benefits from high humidity provided by misting the foliage or by placing the pot on a humidity tray. Make a humidity tray by putting a layer of pebbles in a tray or shallow bowl add just enough water to wet the pebbles. Set the pot on the wet pebbles. Don't add too much water, as the bottom of the pot should never stand in water.
Indoors or out, stromanthe benefits from biweekly feedings with a regular water-soluble fertilizer. Withhold fertilizer during the short days of fall and winter, and then resume normal feeding in the spring.
Sunlight and Temperature
Outdoors, stromanthe needs a shady spot away from direct sun. While morning sunlight is acceptable, too much direct, bright sunlight burns the leaves, creating unsightly discolorations. Place indoor-grown stromanthe in bright, but indirect sunlight. Avoid hot windows with a southern exposure and don't place the plant too near the glass, which is hot during the day and cold at night. Don't expose stromanthe to temperatures below 60 degrees F.