Calathea crotalifera aka Rattlesnake Plant

Calathea crotalifera belongs to the Marantaceae family. This tropical plant lives for more than one year. Its home range runs from central Mexico to southern tropical America. It grows in wet parts of the tropics, including rain forests. People call it yellow rattleshaker or rattlesnake plant. They have brought it to Hawaii and Puerto Rico. In Hawaii, some plants have spread beyond gardens. These grow in sites that are somewhat wet.

This plant stays green all year and grows in clumps. These rise from rhizomes, which are stems below the soil. Its large, glossy leaves give it much of its garden appeal. Each simple leaf has one blade, with no hairs. The leaves grow in turn along the stem. They range from oval to lance-shaped, like a spear tip. Their tops are dark green, with paler green along the midrib. The leaf backs are gray-green and may have purple edges. Pinnate veins branch from the main vein into parallel side veins. The leaf patterns help explain the rattlesnake name.

Upright flower spikes bear layers of showy yellow bracts. These leaf-like parts give the flower heads their rattle-like shape. Small, tube-shaped flowers grow out along the bract edges. Each flower has three lobes that differ in size. It blooms in spring and summer, but seldom indoors. The source lists flower heads of 0.17–0.33 feet [0.05–0.10 metres]. Some reach 0.83 feet [0.25 metres]. Egg-shaped seed cases, called capsules, form after the flowers. They hold dark blue seeds, with white flesh around them. Bees and other pollinators visit the plant.

Grow it in rich soil that drains well but stays moist. For plants in pots, use a peaty potting mix. Give it bright shade or light that passes through a screen. It can take some early morning sun. But direct sun can scorch its leaves. Indoor plants need moist air and warmth of 65–75°F. Keep them out of drafts and away from sharp changes in heat. Water regularly while the plant grows. Do not leave the soil wet. Feed with balanced fertilizer each month from April through August. Cut back on both water and fertilizer in winter. Its listed outdoor hardiness range is USDA zones 11–12.

Use it as a leafy accent or a specimen plant. Outside the tropics, grow it in a pot indoors. Split clumps by division to make new plants. Indoor care can be hard, though few pests or diseases cause grave problems. Watch for aphids, scale, mealybugs, and spider mites. Leaf spots may form as well. Dry air can make leaves curl or turn brown. NC State lists it as non-toxic to cats, dogs, and horses. The supplied evidence does not show any edible uses.