Dieffenbachia seguine aka Dumb Cane

Dieffenbachia seguine, or dumb cane, belongs to the arum family. This evergreen perennial comes from the Caribbean and tropical South America. It grows in wet tropical climates. People grow it indoors for its large, patterned leaves. It also suits containers in greenhouses and conservatories. Its leaves provide colour even when the plant does not flower.

North Carolina State gives a height of 3–8 feet [0.9–2.4 metres]. Plants spread 2–3 feet [0.6–0.9 metres] across. RHS gives a taller range, reaching 13 feet [4 metres]. Its green stems are thick, fleshy, and shaped like canes. Old leaves leave rings around the stems. The plant has few branches, with leaves near the top. Each leaf grows on its own stalk, alternating along the stem. The glossy blades have smooth edges and pointed tips. Their shape ranges from broad ovals to longer, narrow forms. Cream, white, or yellow marks break up the green surface.

Flowers and fruit seldom appear on plants grown indoors. A pale green or white spathe surrounds the white spadix. The spathe forms a curved hood around this flower spike. Small green drupes turn red as they ripen. The leaves remain the main reason to grow this plant. Missouri Botanical Garden describes both flowers and fruit as showy.

Give it bright light filtered from direct sun. It can tolerate shade, but needs protection from cold drafts. Use loose, rich soil that drains well. RHS recommends peat-free compost with a loam base. The plant prefers high humidity and moderate watering during growth. Let the top inch of soil dry before watering again. Reduce watering in winter, when RHS also recommends more light. Feed monthly during growth with a balanced liquid fertiliser. RHS rates it H1A, for warm shelter throughout the year. Missouri Botanical Garden lists USDA zones 10–12. It needs no routine pruning. Stem cuttings and air layering offer ways to raise new plants.

Aphids, mites, scale, whiteflies, fungus gnats, and mealybugs may cause trouble. Leaf spot, root rot, and blight can also occur. The plant is poisonous to people and pets, not food. Chewing leaves can burn and swell the mouth and throat. It may make speech and swallowing difficult. Nausea, vomiting, and diarrhoea can follow. Sap can irritate skin and harm the eyes. Wear gloves when handling it, and wash hands afterwards. Keep it away from children and pets that chew plants.