The Epiphyllum, often called the Orchid Cactus, is a genus of flowering epiphytic cacti native to the tropical rainforests of Central and South America. Unlike desert cacti, these plants grow on trees in their natural habitat, receiving filtered sunlight and high humidity. Their epiphytic nature means care requirements differ significantly from arid-climate cacti, demanding a focus on drainage, light, and humidity to encourage spectacular, often fragrant, blooms.
Light and Temperature Requirements
Epiphyllums thrive in bright, indirect, or filtered light, which mimics the dappled canopy of their jungle home. Direct, intense midday sun, particularly in the summer, can quickly scorch the flattened, leaf-like stems, leading to white scabbing or yellowing. A few hours of gentle morning sun is acceptable, but the plant must be protected from harsh, direct rays throughout the rest of the day.
Epiphyllums prefer warmer temperatures during their active growing season, ideally between 60°F and 80°F (16°C to 27°C) from spring to fall. They are not frost-tolerant and must be protected from cold drafts; temperatures below 50°F (10°C) are damaging. As tropical plants, they appreciate moderate to high humidity levels. Placing the container on a tray filled with damp gravel, ensuring the water level remains below the pot’s base, can help create a more humid microclimate.
Watering and Potting Medium
Epiphyllums need more consistent moisture than desert cacti, but they are extremely sensitive to standing water. During the spring and summer growing season, water thoroughly whenever the top inch or two of the potting mix feels dry to the touch. Let the excess water drain completely from the pot, as prolonged saturation quickly leads to root rot.
The potting medium must be highly porous and well-draining to allow for root aeration. Standard commercial potting soil is often too dense and should be amended heavily or avoided entirely.
An appropriate mix can be created using commercial potting soil or loam combined with materials to ensure rapid drainage. These materials include orchid bark, perlite, pumice, or horticultural grit. The ideal medium should be slightly acidic, and some growers incorporate organic materials like oak leaf mold or sphagnum moss to mimic the plant’s natural environment.
Promoting Blooms
Initiating blooms requires manipulating the plant’s environment. Most varieties require a distinct “winter rest” period to set flower buds, typically beginning in late fall or early winter. During this time, the plant should be moved to a cooler location where temperatures consistently drop to between 50°F and 58°F (10°C to 14°C) for a minimum of three to eight weeks.
Watering must be significantly reduced during this cooler rest period, keeping the potting mix only slightly damp but never allowing it to dry out completely. This cool, dry spell encourages the plant to shift its energy toward flower production. Once flower buds become noticeable, the plant can be returned to its warmer, regular growing location and the normal watering schedule can be resumed.
Fertilization promotes flowering but should be approached cautiously, as Epiphyllums are naturally low-nutrient plants. During the active growing season, apply a balanced fertilizer sparingly (e.g., 5-5-5 or 10-10-10 formulation) every two to four weeks. To encourage bud development, switch to a low-nitrogen, high-phosphorus, and high-potassium fertilizer (e.g., 0-10-10 or 2-10-10 formula) just before or at the start of the winter rest period.
Propagation and Long-Term Maintenance
Epiphyllums are readily propagated using stem cuttings. A healthy, mature stem section, typically 6 to 9 inches long, should be cut and then left in a cool, dry, dark location for about ten days. This step allows the cut surface to dry out and form a protective callus, which prevents rot when the cutting is planted.
Once the callus has formed, insert the cutting about 1 to 2 inches deep into a small pot containing the appropriate well-draining mix, ensuring at least two areoles are below the soil line. New plants should be potted into small containers, as Epiphyllums tend to flower best when their roots are somewhat constricted.
Repotting is generally only necessary every two to three years, or when a regularly blooming plant suddenly stops flowering. Repotting should be done after the bloom cycle has finished. When repotting, select a container only slightly larger than the rootball to maintain the desired rootbound condition.