Euphorbia abyssinica (erythraeae form)

Rocky uplands of the Horn of Africa

The erythraeae form belongs to Euphorbia abyssinica, a species native from northeastern Sudan to Somalia, including Eritrea, Ethiopia and Djibouti. It grows in desert, dry shrubland and rocky uplands.

The erythraeae form shares the species’ dry Horn of Africa background, where strong sun and widely spaced rain leave the root zone dry for long periods.

Euphorbia abyssinica (erythraeae form): bright light and dry intervals

• Light: Provide very bright light and introduce several hours of direct sun gradually.
• Watering: Allow the mix to dry completely before watering again. Thorough but infrequent watering is safer than small, frequent amounts.
• Substrate: Choose a coarse, predominantly mineral succulent mix that drains rapidly around the column base.
• Temperature: Warm conditions suit active growth; keep it above 12°C and avoid cold, wet roots.
• Humidity: Ordinary dry indoor air is suitable, with airflow around the stem angles.
• Feeding: Feed lightly every 4–6 weeks only while the columns are actively extending.
• Repotting: Use a snug, weighty container and increase its size gradually as the plant becomes taller.
• 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.
• Winter: Small temporary leaves can fall in a dry rest. Extend the interval between waterings when growth stops rather than watering to replace the lost leaves.

Common problems with Euphorbia abyssinica (erythraeae form)

• Dark, soft tissue at the base: Stop watering and isolate the plant. If it is tall, heavy or unstable, seek experienced help instead of unpotting or cutting it yourself. If it can be handled safely, 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.
• A sunken but firm stem: Check the root zone before watering. Firm roots in completely dry substrate point to thirst and can be watered thoroughly once; damp substrate, a sour smell or loose roots indicate root damage and should not receive more water.
• Dry patches on the exposed side: A firm pale or brown patch after a sudden increase in direct sun is scorch. Move the plant out of hot midday sun and rebuild exposure gradually; softening, darkening or expansion indicates rot instead.
• Firm corking near the base: A dry, stable patch can be normal ageing or an old injury. Mark its edge and monitor it; active rot becomes soft, dark or progressively larger.

Euphorbia milky sap and spines

Cut or broken stems release milky sap that can irritate skin, eyes and the mouth. The spines can also puncture skin, paws or eyes. 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.

The former variety named for Eritrea

Abyssinica refers to Abyssinia. Erythraeae is linked with Eritrea. The name Euphorbia abyssinica var. erythraeae is now treated as a synonym of the species.

Euphorbia has carried its botanical genus name since Linnaeus published it in Species Plantarum in 1753. Johann Friedrich Gmelin described Euphorbia abyssinica in Systema Naturae in 1791. Alwin Berger published the historical variety erythraeae in Sukkulente Euphorbien in 1907, in a work dated 1906.