Stromanthe is a genus of plants native to tropical rainforests. There are 13 species of Stromanthe, though only a few are commonly cultivated. They have striking foliage, which makes them popular houseplants in temperate climates, and favorite garden plants in warm, humid areas.
Nurseries most commonly sell the species known as Stromanthe sanguinea, which goes by the common names Tricolor or Triostar. The Burle Marx cultivar is also grown domestically. The plants are members of the Marantaceae family, tropical plants that have a distinguishing feature of large, starchy roots, and arrowroot is one example.
Triostars grow to between two and five feet (.6 to 1.5 m) tall and may spread their leaves one to five feet (.3 to 1.5 m) wide. Their long, evergreen leaves have a base color of dark green, but are variegated, and usually have white on the tops. The undersides of the leaves are a shade of dark or hot pink. At night, these leaves fold together, but they are open and track the sun during the day.
These plants are known for their multi-colored leaves, but Triostar plants produce flowers as well. These blooms are pink, like the undersides of the leaves, and are surrounded by small, petal-like orange leaves. They grow in clusters atop tall stems and usually bloom in mid-spring.
The Burle Marx variety of Stromanthe is considerably smaller than the Triostar, reaching only one to one and a half feet ( .3 to .45 m) in height and spreading to a foot (.3 m) or so in width. Its smaller, oblong leaves have a pattern of dark green and light green to white. The flowers of Burle Marx plants are white, and can bloom from late spring to early fall.
Like other tropical plants, Stromanthe needs humidity for optimum growing conditions. Growing them outdoors in tropical or subtropical locations will satisfy this requirement. Indoors, they grow best in rooms that are humidified.
Stromanthe grows best in loamy or sandy soils that are acidic or neutral, with a high content of organic matter. A potting mix should have good drainage and be kept evenly moist. Outdoors, these plants should be placed in light shade or partial shade, as too much sun can burn the leaves, causing brown spots.
The plants may be able to survive a light frost, but they are happier when temperatures don't drop below 40°F (4.4°C). Dry soil, dry air, and cold weather can all cause the leaves to turn brown. The plant may regrow once the weather turns warmer, however.