Euphorbia bosseri is part of the Euphorbiaceae family and its’ native range is S. Central & SE. Madagascar. It is a semi-succulent subshrub and grows primarily in the desert or dry shrubland biome, typically forming mats in the dry deciduous Alluaudia forests. This species is considered vulnerable in the wild due to the continuing decline of its habitat; climate change has resulted in landslides and flooding.
The flattened stems are a mottled red-brown colour, they are firm and totally leafless. The plant will sunstress (become more pink) if exposed to lots of light. The flowers are orange-gold, very small and aggregated into a cluster known as a cyathium (plural cyathia). It is self fertilising with explosive seed pods!
Genus name comes from the Latin euphorbea, named after Euphorbus, Greek physician to the reputed discoverer of the plant (King Juba II of Numidia). Specific epithet honours Jean Marie Bosser, a botanist who extensively studied the plants of Madagascar.
This plant is one of the more poisonous spurges; the latex is very bitter and acrid, containing diterpenes and is considered highly toxic. Sap may cause severe skin irritation & eye pain, including temporary blindness that can last several days. All parts are highly toxic, possibly fatal, if ingested.
Pot: ø 12cm.
Height: Approximately 30cm from base of pot.
Light: Allow the plant to see the sun for as many hours of the day as possible; the plant ought to be able to see sun from where it is positioned in the home.
Water: Allow the potting mix to dry out completely in between waterings; Euphorbia store the water they need for photosynthesis inside their stems. Before watering, aerate the potting mix with a few pokes of a skewer or blunt stick, pour water slowly over the top of the substrate and allow the water to pass through the drainage holes.
Potting mix: A well draining mix composed primarily of non-organic material such as clay, pumice, lava grit with a little coco-coir. You can easily propagate by taking stem cuttings (wear gloves/wash hands) and allowing them to suberize (callus) for up to a week before planting into potting mix. These plants prefer to be in a smaller pot so don’t rush to pot up.
Fertilising: Feed every few waterings during the growing season. You can dilute fertiliser to half the recommended amount but never add more.
Temperature: Spring and summer 18-30˚C, autumn and winter 10-13˚C
Humidity: Average humidity; if the humidity is particularly high, good ventilation is key to prevent mildew and fungal disease.
Euphorbia are toxic, keep out of reach of pets and children.