Euphorbia alluaudii

Madagascar’s dry regions

Euphorbia alluaudii grows naturally only in Madagascar. Its habitats include the dry bush of the southwest and rocky inland areas with a long dry season.

Madagascar’s long dry season leaves Euphorbia alluaudii accustomed to bright warmth and months when its rocky root zone receives very little moisture.

Euphorbia alluaudii: watering through growth and dormancy

• Light: Strong light and gradually introduced direct sun support firm, compact stem growth.
• Watering: While new stems or leaves are appearing, water after the mix has dried almost completely. Once the plant becomes leafless and stops growing, leave it dry for much longer.
• Substrate: Use a coarse, fast-draining mix with a high mineral content.
• Temperature: Warmth encourages active growth; protect the plant from temperatures below 12°C.
• Humidity: Low to average humidity is appropriate, provided the fine branches have airflow.
• Feeding: Feed lightly every 4–6 weeks during visible growth and pause when the plant is resting.
• Repotting: Use a stable pot that fits the roots closely and does not hold excess wet substrate.
• Propagation: Take a healthy stem or branch cutting during active growth, let the cut surface callus fully and root it in a coarse mineral mix.
• Dormancy: Seasonal leaf loss is normal. Wait for renewed growth before returning to the more regular watering rhythm.

Common problems with Euphorbia alluaudii

• Dark, soft tissue at the base: Stop watering and isolate the plant. Wear nitrile gloves, long sleeves and eye protection, and keep the milky latex off skin and eyes. Unpot the plant and remove rotten tissue with a disinfected blade, clean the tool and work surface, then let every wound seal fully before placing firm tissue in dry mineral substrate.
• Small leaves dropping from firm stems: Temporary leaves can fall during a normal rest or when the root zone becomes drier. If the stems and growing points remain firm, reduce watering and wait for active buds. Soft tissue, blackening or leaf drop during wet conditions indicates a root problem instead.
• White wax around slender branch joints: Inspect the narrow branch forks, nodes and small leaf scars for mealybugs or scale. Isolate the plant and apply a product labelled for the identified pest without soaking the fine stems or root zone.
• Thin, elongated branch extensions: New branches that are unusually thin, flexible or widely spaced indicate insufficient usable light during active growth. Increase brightness gradually and judge the response from subsequent branching.

Euphorbia milky sap irritates skin and eyes

Cut or broken stems release milky sap that can irritate skin, eyes and the mouth. Swallowing plant material may cause mouth irritation, drooling, vomiting or diarrhoea. Wear gloves and eye protection when cutting or handling damaged growth. If sap touches the skin, wash it off with soap and water. If it enters an eye, rinse continuously with water for 15–20 minutes and seek medical advice. If a person swallows any part, rinse the mouth and contact a poison centre or doctor for advice; if a pet eats the plant, contact a veterinarian.

Named for Charles Alluaud

Alluaudii honours French naturalist and explorer Charles Alluaud. The genus Euphorbia commemorates Euphorbus, physician to King Juba II of Mauretania.

In 1753, Linnaeus published the genus Euphorbia in Species Plantarum. Emmanuel Drake del Castillo described Euphorbia alluaudii in the Bulletin du Muséum d’Histoire Naturelle in 1903.