Epiphyllum oxypetalum aka Dutchman's Pipe Cactus

Epiphyllum oxypetalum, or queen of the night, belongs to the cactus family. Its native range runs from Mexico south to Nicaragua. This evergreen plant grows in moist tropical forests. It roots on trees and other plants, or on rocks. Its thick stems store water, but it needs more moisture than desert cacti. Gardeners grow it for its large, scented night flowers.

The plant branches freely and can stand upright, climb, or trail. Garden plants reach about 5–10 feet [1.5–3 metres] tall. They spread about 1.6–3.3 feet [0.5–1 metre] wide. Long stems can reach nearly 20 feet [6 metres]. Round main stems bear flat green branches that look like leaves. These are phylloclades, not true leaves, and have wavy or scalloped edges. The plant lacks spines, and its smooth branches stay green year-round. Flat branches can reach 1.3 feet [0.4 metres] long.

Flowers form along the edges of the flat stems. Their long tubes carry broad white blooms with a strong scent. The outer flower parts may show pink or yellow tones. Flowers can span about 0.8 feet [0.25 metres]. They open near dusk and fade by the next morning. Blooming falls in late spring and early summer. Indoor plants may flower at less set times. Bats and moths pollinate the flowers in the wild. Fruit forms rarely and ripens to a purple-red shade. Each oblong fruit holds white flesh and small black seeds.

Grow this cactus in bright light without harsh afternoon sun. Use a rich potting mix that lets excess water drain. Loam or sand can suit it with added organic matter. Water well during spring and summer, then let the surface dry. Give less water in fall and winter as growth slows. RHS advises six weeks of light watering after flowering. Moderate to high humidity suits the plant. Protect it from frost; RHS rates it H1B. NC State lists USDA zones 10–11. It suits pots, hanging baskets, greenhouses, and warm-season outdoor displays.

Mealybugs, mites, and scale can attack the stems. Poor drainage or too much water can cause root rot. Poor airflow can allow powdery mildew, while direct sun can scorch stems. Stem cuttings offer a simple way to grow new plants. The fruit is edible. Useful Tropical Plants also records flowers cooked in soup. NC State does not recognise the flowers as food. Useful Tropical Plants lists no known hazards, but gives no pet-safety details. Sources record folk medicinal uses, not proof that treatments work.