Epiphyllum is a genus of tree-dwelling tropical plants in the cactus family. Commonly called orchid cacti, epiphyllum plants are epiphytic and grow attached to tree branches or on rocks. The fibrous roots anchor the plant to the growing surface and absorb nutrients and water from the air. Orchid cacti produce white and pale yellow blossoms that bloom at night. There are many hybrid versions of this plant with an expanding range of flower color and leaf shape.
Orchid cacti are native to Mexico, South America and Central America, where they grow in humid, tropical forests. Known alternately as leaf cacti, epiphyllum flowers appear to grow from the surface of what look to be leaves. The leaf-like part, as with all cacti, is not a true leaf but a thickened stem that has adapted to perform photosynthesis. The epiphyllum lacks the sharp spine of its desert-dwelling relatives.
Adapted to humid, tropical climates, the epiphyllum is better suited as a houseplant in temperate and sub-tropical climates. These types of plants take well to life indoors and require minimal maintenance. A well-draining, loose potting mix should be used so the roots stay slightly damp but not saturated or smothered in heavy, wet soil. Good potting mediums include mixtures of coarse sand, leaf mold, finely shredded bark, perlite, vermiculite and peat moss. A porous potting soil mix formulated for cacti is also suitable.
Potted epiphyllum can be moved outdoors during warm weather and placed in an area with partial shade. Indoors, these types of plants thrive in a light area with filtered, indirect sunlight. The soil medium should be kept slightly damp but never saturated, and standing water should be avoided. The pot can be placed in a sink after watering to drain completely. When using saucers under the pot to protect surfaces, they should be checked frequently and emptied of standing water.
In warm climates where winter temperatures do not drop below 40 degrees Fahrenheit (about 4 C), epiphyllum can be grown outdoors in rocky, well-draining soil. A rock garden or rock wall provides good growing conditions. The night-blooming flowers make this exotic cactus a natural part of a night or moon garden, where the flowers are selected to reflect moonlight.
Epiphyllum is easy to propagate by rooting a section of the stem. A 6- to 12-inch (15- to 30-cm) section of the succulent green stem works best. After removing the cutting from the plant, it should be allowed to dry out for one to two weeks. After the drying period, the bottom third of the cutting should be buried in a pot filled with a porous potting mix.