African milkweed, a striking succulent, offers a unique aesthetic to any indoor or outdoor plant collection. Its distinctive upright growth and architectural form make it a favored choice for a low-maintenance yet visually appealing plant. This resilient succulent thrives in various conditions, adding an exotic touch.
What is African Milkweed?
Despite its common name, African milkweed is not a true milkweed from the Asclepias genus. It is a succulent belonging to the Euphorbia genus, specifically Euphorbia trigona. This distinction is important: unlike true milkweeds, Euphorbia trigona does not host monarch butterflies and has different characteristics.
This plant has an upright, columnar growth habit with multiple branching stems. Its fleshy stems are typically green, though cultivars like ‘Rubra’ exhibit a reddish hue. Stems are distinctly triangular in cross-section, with ridged edges, small thorns, and intermittent teardrop-shaped leaves. Native to central Africa, particularly regions like Angola, Gabon, and Congo, Euphorbia trigona is well-adapted to arid environments, storing water in its thick stems. Its unique appearance often leads to it being mistaken for a cactus, earning nicknames like “cathedral cactus” or “candelabra cactus.”
African Milkweed Care
Light
African milkweed thrives in bright, indirect light. A south-facing window provides ample natural light, or an east/west-facing window with at least four hours of bright, indirect sunlight daily works. It tolerates some direct morning sun, but intense midday sunlight can cause scorching and brown patches on the leaves. Adequate light is especially important for ‘Rubra’ cultivars to maintain vibrant coloration.
Soil
Well-draining soil is paramount for African milkweed to prevent root rot. A commercial cactus or succulent mix is ideal, or create your own by combining potting soil with perlite and sand to enhance drainage. The pot must have drainage holes to prevent waterlogging. The plant prefers a soil pH from mildly acidic to mildly alkaline (6.1-7.8).
Water
African milkweed prefers a “soak and dry” watering method. It is best to water thoroughly, allowing the soil to dry out completely between waterings. Overwatering is a frequent cause of problems, leading to root rot and other issues.
During the spring and summer growing season, water weekly, ensuring the top inch or two of soil is dry before rewatering. In fall and winter, during dormancy, reduce watering to once every four to six weeks, or when the soil is entirely dry. It is safer to underwater this succulent than to overwater it.
Temperature and Humidity
As a tropical plant, African milkweed prefers warmer temperatures, ideally between 63-75°F (17-24°C). It suffers below 55°F (13°C) and is not frost-tolerant. If grown outdoors, bring it indoors before temperatures consistently fall below 40°F (4°C). The plant tolerates average household humidity and does not require high humidity, making it suitable for most indoor environments.
Fertilizer
During its active growing season, typically from spring through late summer, African milkweed benefits from occasional fertilization. Apply a balanced, diluted liquid fertilizer every few months to support its growth. Avoid fertilizing during dormant winter months.
Propagating African Milkweed
Propagating African milkweed is typically achieved through stem cuttings, a straightforward process. The best time is during the warm seasons of spring or early summer when the plant is actively growing. Select a healthy branch at least 4-6 inches long.
Use a sharp, sterilized knife or shears to make a clean cut, ideally at a 45-degree angle to increase the surface area for rooting. Immediately after cutting, the plant will exude milky white sap. To stop sap flow, rinse the cut end under cold running water for about 30 seconds. Allow the cutting to callus in a dry, shaded location for several days to two weeks. This callusing process is important as it helps prevent rot once planted.
Once calloused, plant the cutting in a small pot with well-draining cactus or succulent potting mix. Insert it a couple of inches deep to ensure stability. Initially, water very sparingly, only moistening the soil, and rewater only when the top inch of soil feels dry to the touch. Place the cutting in bright, indirect light, avoiding direct sunlight. Roots typically form within a few weeks to two months, after which it can be cared for like a mature plant.
Safety Precautions
African milkweed produces a milky white sap, also known as latex, that is an irritant. This toxic sap can cause skin irritation, rashes, or blistering if it comes into contact with the skin. It is also harmful if ingested and can cause painful inflammation if it contacts mucous membranes like the eyes or mouth. Sap exposure, especially during cutting or pruning, may also lead to breathing difficulties in some individuals.
When handling African milkweed, especially during pruning or propagation, it is important to wear protective gear. Gloves and eye protection are recommended to prevent direct contact with the sap. If sap gets on skin, wash immediately with soap and water.
If sap enters eyes, flush with running water for 10-15 minutes and seek medical attention promptly. In case of ingestion, contact a poison control center for medical advice. It is also advisable to keep African milkweed plants out of reach of children and pets due to its toxicity.
Troubleshooting Common Problems
African milkweed is generally a robust plant, but specific issues can arise from environmental factors or pests. One of the most common problems is overwatering, which can lead to root rot. Symptoms include mushy stems, yellowing leaves, and wilting, as roots are deprived of oxygen. To correct this, ensure soil dries completely between waterings and use a well-draining potting mix.
Pest infestations can also occur, though African milkweed is relatively resistant. Common pests include mealybugs, spider mites, and aphids, which can appear as small dots, webbing, or sticky residue on the plant. Manage pests by regularly inspecting the plant and treating with insecticidal soap or neem oil. Manual removal of mealybugs is also an option.
Another issue is leggy growth, where the plant stretches excessively, indicating insufficient light. This can result in a less compact and attractive appearance. Providing more bright, indirect light can help correct this and encourage balanced growth. While African milkweed is resilient, consistent monitoring of watering and light conditions prevents most common problems.