The Variegated African Milk Tree (Euphorbia trigona ‘Rubra’ or ‘Red Devil’) is a distinctive succulent prized for its architectural form and vibrant coloration. Its upright, candelabra-like stems, often tinged with reddish hues, make it a popular choice for indoor plant enthusiasts. Despite its cactus-like appearance with prominent ridges and thorns, this plant is a succulent, not a true cactus. Its striking silhouette and ease of care contribute to its widespread appeal.
Caring for Your Variegated African Milk Tree
Light Requirements
The African Milk Tree thrives in bright, indirect sunlight. A south-facing window indoors provides adequate light. While it tolerates some direct sun, excessive amounts can scorch its stems and leaves, potentially affecting its variegation. Insufficient light may cause etiolation, where stems become elongated and pale. Consistent, bright light is key for maintaining its compact growth and vibrant coloring.
Watering Needs
As a succulent, the African Milk Tree stores water in its fleshy stems, making it highly drought-tolerant. Allow the soil to dry out completely between waterings to prevent root rot, which is a common issue. During active growth in spring and summer, watering once a week or when the top inch of soil feels dry is generally sufficient. During its dormant period in fall and winter, reduce watering significantly, to once every 4-6 weeks, or only when the soil is completely dry. Overwatering is a frequent mistake, so it is always better to err on the side of underwatering.
Soil and Potting
A well-draining soil mix is essential for the African Milk Tree to prevent waterlogging and root rot. A commercial cactus or succulent mix is ideal, or create your own by combining potting soil with perlite and coarse sand to enhance drainage. The plant prefers a soil pH between 6.1 and 7.8, which is slightly acidic to neutral. When choosing a pot, opt for one with drainage holes, preferably made of porous terracotta, which helps absorb excess moisture. Repotting may be necessary every 2-3 years, or when the plant becomes root-bound, selecting a pot only slightly larger than the previous one for stability.
Temperature and Humidity
The African Milk Tree prefers warm temperatures, thriving between 65°F and 85°F (18°C to 29°C). It is not frost-tolerant and should be protected from temperatures below 40°F (4°C); prolonged exposure below 50°F (10°C) can cause harm. If grown outdoors in suitable climates (USDA Zones 9-11), bring it indoors during colder months. This plant adapts well to low to moderate household humidity, generally not requiring additional misting. Good air circulation is beneficial to prevent fungal issues.
Feeding Schedule
During its active growing period in spring and summer, the African Milk Tree benefits from occasional fertilization. Use a balanced, low-nitrogen fertilizer or a specialized cactus and succulent fertilizer. Dilute the fertilizer to half strength and apply it monthly during these seasons. Avoid fertilizing in the fall and winter when the plant enters dormancy, as this can lead to leggy growth or root damage. Over-fertilization can cause a buildup of salts in the soil, which can be detrimental to the plant’s health.
Propagating New Plants
Propagating the African Milk Tree is commonly achieved through stem cuttings during active growth (warmer months). Select a healthy stem section, at least 4-6 inches long, and use a sharp, sterilized knife or pruners for a clean cut. After taking the cutting, allow the cut end to form a callus. Place the cutting in a dry, shaded location for five to seven days until the cut surface dries and hardens; this callusing prevents rot. Once callused, plant the cutting about an inch deep in a pot filled with a well-draining cactus or succulent mix. Water sparingly until roots establish, which typically takes about two months.
Addressing Common Challenges
Leaf drop can occur due to overwatering, underwatering, or sudden temperature fluctuations. If leaves are dry and crispy, it may indicate insufficient water, while mushy stems and yellowing leaves suggest overwatering. Adjusting the watering schedule and ensuring stable temperatures can help prevent this problem.
Etiolation, or stretching of the stems, is a sign of inadequate light. The plant will grow long, pale, and spindly as it searches for more light. Moving the plant to a brighter location with more indirect sunlight can help correct this issue, though stretched growth will not revert.
Pests like mealybugs and spider mites can occasionally affect African Milk Trees. Regular inspection of the plant’s stems and leaves can help detect these pests early. Treating infestations with insecticidal soap or neem oil can effectively manage them.
Stem or root rot, typically caused by overwatering, manifests as mushy or discolored stems. If rot is identified, it is important to stop watering immediately and allow the soil to dry out. In severe cases, the affected parts may need to be pruned, and the plant repotted into fresh, dry soil.
Important Safety Information
The African Milk Tree, like other Euphorbia species, produces a milky white sap (latex) when its stems are cut or damaged. This sap is toxic and can cause significant irritation upon contact. Skin exposure may result in redness, itching, burning sensations, or the development of a rash or blisters. Eye contact is particularly serious, potentially leading to intense pain, inflammation, conjunctivitis, and, in severe cases, temporary blindness. If the sap is ingested, it can cause gastrointestinal upset, including nausea, vomiting, and diarrhea in both humans and pets.
It is important to wear gloves and eye protection when handling the plant, especially during pruning or propagation, to avoid exposure to the sap. Always wash hands thoroughly after touching the plant. To prevent accidental exposure, keep the African Milk Tree out of reach of children and pets.