Euphorbia lactea ‘Variegata’, commonly sold as the Crested Elkhorn or ‘White Ghost’, is a striking, sculptural succulent prized for its unusual fan-shaped or wavy growth habit. Although often mistakenly identified as a cactus, it belongs to the Euphorbia genus, known for its fleshy stems and milky sap. Most specimens are composite plants, meaning the variegated top growth, called the scion, is grafted onto a hardier green rootstock, typically from a different Euphorbia species. This grafting technique ensures the survival and robust growth of the ornamental top, as the variegated portion lacks sufficient chlorophyll.
Establishing the Ideal Habitat
Successful growth of this succulent requires intense light to maintain its compact form and vibrant coloration. The plant thrives in locations that receive extremely bright, indirect sunlight for much of the day, such as a position near a south-facing window. Insufficient light exposure causes the stems to stretch and thin, a process known as etiolation, which permanently weakens the structure. However, because the white and pink areas contain little chlorophyll, intense, direct afternoon sun can cause irreversible scorch marks.
These succulents prefer warm, stable conditions, with an ideal temperature range between 60°F and 85°F. Protect the plant from cold drafts and temperature fluctuations, as exposure to temperatures below 50°F can cause significant stress or permanent tissue damage. The potting medium must be formulated for rapid drainage to prevent water retention around the roots.
A specialized, gritty mix is required, often consisting of commercial cactus soil amended with coarse inorganic materials like perlite, pumice, or lava rock in a ratio of at least 50% grit. The container must have a large drainage hole at the base to allow excess moisture to escape freely. Using a slightly heavier pot provides necessary stability, as the crested, variegated top can become quite heavy.
Routine Care and Hydration
Watering practices are the most delicate part of caring for this succulent, as overwatering is the leading cause of decline. The correct technique involves the “soak and dry” method, where the plant is watered thoroughly until it drains from the bottom, and then the soil is allowed to dry out completely before the next application. During the active growing season of spring and summer, this thorough watering may be necessary every two to three weeks, depending on environmental factors like heat and air circulation.
In the cooler, darker months of fall and winter, the plant enters a period of dormancy and requires significantly less water. During this time, water should be reduced to a near-total cessation, perhaps a small application once a month or less. When the plant begins to show signs of thirst, such as a slight wrinkling or softening of the stems, it signals the ideal time for a deep watering. Fertilization should only occur during the spring and summer growing months to support new growth.
Use a balanced liquid fertilizer diluted to half-strength, or a specialized cactus formula, and apply it no more than once a month. Little pruning is typically required, but regular attention must be paid to the rootstock below the graft line. The green rootstock may occasionally produce shoots, called reversion, which must be immediately removed. If left to grow, these revert shoots will divert energy away from the variegated top, causing the scion to wither.
Troubleshooting and Safety Precautions
The appearance of dark, soft, or mushy spots, particularly near the base, is a clear indication of overwatering and the onset of fatal root rot. Conversely, prolonged periods without water will cause the stems to shrivel and look deflated, a sign that a deep, restorative watering is needed immediately. If the plant is moved too quickly into intense light, the white portions may develop brown, crispy patches, which is a form of sunburn that cannot be healed.
Pest management primarily involves vigilance against common succulent pests like mealybugs and spider mites. Mealybugs often hide in the crevices of the crested growth, appearing as small, cottony masses. They can be effectively treated by dabbing them directly with a cotton swab soaked in rubbing alcohol.
The milky white latex sap, known as laticifer, is a caustic irritant that can cause severe skin inflammation, rashes, and a strong burning sensation upon contact. If the sap contacts the eyes, it can result in extreme pain and temporary blindness. It is imperative to wear thick gloves and eye protection when pruning, repotting, or handling the plant to avoid accidental exposure. If skin contact occurs, immediately wash the area thoroughly with soap and water, and seek medical attention if the sap enters the eyes.