Euphorbia alluaudii

Madagascan dryland background of Euphorbia alluaudii

Euphorbia alluaudii is native to Madagascar. In the wild, it grows as a succulent shrub or small tree in very dry bush, on exposed rock faces and in other open sites with fast-draining ground.

These habitats are warm and exposed, with long dry periods between rains.

Indoor growing requirements for Euphorbia alluaudii

• Pruning and repotting: Shorten selected branches if the plant becomes too wide or tall. Repot when roots fill the container, and use a heavy pot for a large plant.
• Light: Use a very bright position and introduce direct sun gradually. After a move, start with a short period of direct sun and increase it gradually.
• Watering: Water deeply once the potting mix has dried completely. When branch growth slows or pauses, water less often and make sure the mix is fully dry each time.
• Potting mix: A loose succulent mix with grit or pumice helps the fine stem bases dry quickly after watering.
• Temperature: A warm room suits it best. Keep temperatures above about 10 °C, and wait longer between waterings if the room is cool.
• Humidity and airflow: Standard indoor humidity is suitable. Keep some space between the branches so air can move freely.
• Feeding: Give a small amount of succulent fertiliser while new branches are growing.
• Propagation: Take a healthy stem cutting and let the cut dry fully before rooting it in a fast-draining mix. Wear gloves and eye protection because the branches release irritating latex.

Common issues with Euphorbia alluaudii

• The lower stems become soft where they meet the mix: Potting mix that stays wet can cause rot at the base. Stop watering, unpot the plant and cut away all rotten roots or stems with a clean tool until only firm, healthy tissue remains. Discard the rot and let the cuts seal before repotting or rooting the healthy plant.
• Fresh branches are unusually thin and widely spaced: Thin, widely spaced fresh branches often indicate that the light is too weak. Raise the light level gradually and keep the plant in a consistently bright position.
• Tips wrinkle while the base stays firm: If the roots are firm and healthy and the mix is dry, the plant may simply need water. Water thoroughly once and let all excess drain.
• Cottony patches or small fixed scales appear at branch forks: Inspect the dense branches for mealybugs or scale. Isolate the plant, remove visible pests and use a treatment labelled for the insect you find, including repeat applications only as directed.

Euphorbia alluaudii is toxic to people and pets

• Keep this plant away from children, cats and dogs, and avoid contact with its milky sap.
• The sap contains irritating diterpene esters that can burn the mouth and damage skin or eyes.
• Sap exposure may cause painful irritation, while swallowing plant material can cause vomiting or stomach pain. Contact a veterinarian or medical professional promptly, especially after eye exposure.

Euphorbia alluaudii: where the name comes from

Euphorbia honours Euphorbus. Alluaudii honours French naturalist and explorer Charles Alluaud.

Carl Linnaeus established the genus Euphorbia in 1753 in Species Plantarum, page 450.

Emmanuel Drake del Castillo first described Euphorbia alluaudii in 1903 in Bulletin du Muséum d’Histoire Naturelle (Paris), volume 9, page 43.