Epiphyllum, often called “orchid cacti,” are epiphytic plants. They naturally grow on other plants, like trees, in their native tropical rainforest habitats, rather than in soil. Understanding their specific needs, which differ from typical desert cacti, is key to cultivating these beautiful bloomers.
Essential Growing Conditions
Light Needs
Epiphyllum thrive in bright, indirect light, mimicking the dappled sunlight they receive under a tree canopy. Placing them near an east or north-facing window is ideal indoors. Direct midday sun can scorch their stems, leading to discoloration or white scabbing. Insufficient light may result in leggy growth and a lack of flowers. If your plant is near a south or west-facing window, using sheer curtains helps diffuse intense sunlight.
Watering Practices
Unlike desert cacti, Epiphyllum require regular watering during their active growing season, from spring through fall, but should never be left in standing water. The “soak and dry” method is effective: water thoroughly until it drains from the pot, then allow the top one-third of the potting mix to dry out before watering again. During cooler autumn and winter months, reduce watering significantly, allowing the soil to dry out more between applications to encourage a period of rest.
Ideal Soil Mix
Epiphyllum require a well-draining, airy, and slightly acidic potting mix. A standard peat-based potting mix alone is too dense and can lead to root rot. An ideal blend includes components like orchid bark, perlite, and peat moss or a good quality succulent or cactus mix.
Temperature and Humidity
Epiphyllum prefer warm temperatures (60-80°F / 16-27°C) during their growing season. They are not frost tolerant and need protection from temperatures below 50°F (10°C). Epiphyllum also benefit from moderate to high humidity. In dry indoor environments, humidity can be increased by placing the pot on a pebble tray filled with water (ensuring the pot does not sit directly in the water) or by using a room humidifier.
Fertilization
Fertilize Epiphyllum conservatively to support growth and blooming, avoiding overfeeding as they naturally grow in low-nutrient environments. During the active growing season (spring to fall), apply a balanced, water-soluble fertilizer diluted to half strength every two to four weeks. To promote abundant blooms, a fertilizer with a higher phosphorus content (such as a 2-10-10 ratio) is beneficial in early spring. Withhold all fertilizer during the plant’s dormant period in late fall and winter.
Promoting Abundant Blooms
A cool, dry dormancy period during winter is a key trigger for flower bud formation. Move the plant to a cooler location (50-58°F / 10-14°C) and significantly reduce watering for several weeks. Once flower buds begin to appear, the plant can be returned to warmer conditions and regular watering resumed. Epiphyllum flower best when slightly root-bound; avoid overly large pots for more prolific blooming.
Addressing Common Issues
Lack of blooms is often due to insufficient light, an absence of the necessary cool winter dormancy, or being in a pot that is too large. Yellowing leaves often indicate overwatering (leading to root rot) or occasionally underwatering if stems appear shriveled. Brown tips or edges suggest low humidity or scorching from direct sun.
Watch for mealybugs, aphids, and spider mites. Address these by gently wiping them off with an alcohol-soaked cotton swab or using an appropriate insecticidal soap. Good air circulation also helps prevent fungal issues, especially in humid environments.
Propagating and Repotting
Propagate Epiphyllum from stem cuttings. Select healthy stem sections, 4-9 inches long, and allow the cut end to dry and form a callus for a week to prevent rot. Once callused, insert the cutting vertically about 1-2 inches deep into a well-draining cactus or succulent potting mix. Keep the soil slightly moist, not soggy, and place the cutting in bright, indirect light; rooting occurs within a few weeks.
Repotting is not a frequent task for Epiphyllum. Repot every two to three years, or when the plant outgrows its container or the soil degrades. The best time to repot is after flowering, usually in spring or early summer, to minimize disturbance. Choose a container only one size larger and use fresh, well-draining potting mix.