Huernia macrocarpa, often called the Starfish Flower or Carrion Flower, is a clump-forming succulent native to arid regions of East Africa, including Ethiopia. This informs its preference for dry, warm conditions. The plant features fleshy, glaucous-greyish green stems that are typically four or five-angled and covered in coarse teeth, growing sideways to form dense mats. It produces bell-shaped, five-lobed flowers, ranging from dark purple to reddish with intricate markings, between July and October. These flowers are notable for their scent, which attracts flies for pollination.
Initial Planting and Propagation Techniques
Successful growth requires a substrate that mimics the plant’s native, arid environment. Use a commercial cactus or succulent mix, amended with materials like perlite, pumice, or coarse sand to increase porosity and ensure rapid drainage. The goal is a gritty mixture that allows water to pass through quickly, preventing root moisture retention. Containers must always have drainage holes. Unglazed terracotta pots are often recommended because their porous material allows moisture to evaporate through the sides.
The simplest and most reliable way to create new plants is through stem cuttings. Use a clean, sharp tool to detach a healthy stem section. Let the cut end dry completely for a few days until a protective callous forms over the wound. This step prevents fungal pathogens from entering the tissue and causing rot once the cutting is planted.
Once the callous is firm and dry, insert the cutting into the prepared, well-draining soil mix. During this initial rooting phase, keep the soil lightly moist, but not saturated, until new growth indicates root formation. Propagation from seed is also possible, usually by sowing in moist, sandy peat moss in the spring, but this method yields lower success rates than using cuttings.
Essential Environmental Conditions
Huernia macrocarpa requires bright light to maintain compact growth and encourage flowering. Place the plant in a location that receives ample sunlight, such as an east or west-facing window. While the plant benefits from several hours of light per day, it must be shielded from intense, direct midday sun, especially in hot climates, as this can scorch the fleshy stems.
Temperature management is important for the plant’s health. The species thrives in warm conditions, with daytime temperatures ranging between 65°F and 85°F. It is intolerant of cold temperatures; avoid extended exposure to conditions below 50°F (10°C).
In winter, the plant can tolerate temperatures around 50°F, or brief dips near freezing (0°C), but only if the soil is kept completely dry. Adequate air circulation around the stems is important, especially indoors or in humid environments. Good airflow helps the soil surface dry quickly after watering and reduces the risk of fungal diseases and stem rot.
Watering and Fertilization Schedule
Overwatering is the most common mistake, quickly leading to root and stem rot. The correct approach is the “soak and dry” method: water thoroughly until it runs out of the drainage holes, then allow the soil to dry out completely before the next watering. Before re-watering, confirm the soil is bone-dry several inches down, or throughout the entire pot for smaller containers.
Adjust watering frequency based on the season and the plant’s growth cycle. During the active growing season in spring and summer, the plant requires more frequent watering, sometimes weekly, depending on heat and light levels. As temperatures drop and light decreases in the fall, the plant enters dormancy, and watering must be significantly reduced.
During winter dormancy, the plant needs very little moisture, often only a light watering every four to six weeks to prevent excessive shriveling. Limit fertilization to the active growth period. Apply a balanced liquid fertilizer, formulated for succulents or cacti, once every four to six weeks. Dilute the fertilizer to a quarter or half the strength recommended on the label to prevent root burn, and cease all feeding in the fall and winter.
Troubleshooting Common Growth Problems
The most immediate concern is rot, identifiable by dark patches, yellowing, or a mushy texture in the stems. Rot results directly from overwatering or poor drainage and requires immediate action. Cut away all affected, soft parts completely with a sterile blade. Allow the remaining healthy sections to dry for several days before repotting into fresh, dry soil.
Pest infestations are uncommon but can occur, primarily involving mealybugs and scale insects. These pests typically hide in stem crevices or near the soil line. Treat small infestations by gently swabbing the pests with a cotton swab dipped in rubbing alcohol. For widespread issues, apply insecticidal soap or neem oil, following the product’s instructions.
If the plant is healthy but fails to produce its characteristic star-shaped flowers, the issue is often environmental. Insufficient bright light is the most frequent cause for a failure to bloom. The plant may also not flower if it does not receive a cool, dry rest period during the winter. Mimicking the natural seasonal change by reducing water and keeping the plant in slightly cooler temperatures during dormancy often stimulates flower production.