Euphorbia horrida alba - African milk barrel

Euphorbia horrida 'Alba' is a rare and fascinating variety of Euphorbia horrida, recognisable by its blue-grey to silvery-white stems and prominent thorns. Native to South Africa, this succulent plant forms compact clumps and is well-suited to pot cultivation. Its ribbed, upright or twisted stems with wavy midribs, stand out from the ordinary. An epidermis, covered in a waxy bloom, gives these stems a bluish or silvery, sometimes almost white, appearance, accentuated by light. In summer, it produces small greenish-yellow flowers that contrast with the plant's robust appearance.

Euphorbia horrida 'Alba' (Euphorbia polygona var. alba) is a variety derived from the Euphorbia horrida species, also known as the Bristly Spurge or "African Milk Barrel". It originates from the semi-arid regions of the Great Karoo in South Africa and is a succulent plant adapted to extreme heat and drought conditions. The 'Alba' variety, lighter than the typical species, retains the same upright, columnar habit but displays a unique silvery hue. It forms compact clumps of cylindrical stems measuring 10 to 15 cm in diameter, reaching a maximum height of 60 cm in pots. The deep, wavy midribs are edged with long, rigid, fierce thorns emerging from old inflorescences, measuring up to 4 cm long and taking on brown-red or grey tones. Its discreet cyathia (flowers) appear between late spring and summer. They are greenish-yellow to purple and clustered along the stems. Like all Euphorbias, this plant secretes a toxic white latex, irritating to the skin and mucous membranes.

Caring for Euphorbia horrida 'Alba' is straightforward but requires some precautions. It needs intense light exposure, ideally near a south-facing window. A very well-draining substrate, composed of a mix of cactus compost and perlite, is essential to prevent root rot. Watering should be moderate during the growth period (spring-summer), allowing the substrate to dry completely between waterings, and almost none in winter. This spurge tolerates temperatures between 18°C and 26°C, though it is hardy down to -4°C. In pots, it can be grown in hanging containers or on a stone support to mimic its rocky habitat.

Euphorbia horrida 'Alba' pairs well with other architectural succulents, such as Euphorbia enopla or Euphorbia resinifera, to create contrasts in form and texture. It also complements globular cacti like Echinocactus grusonii or striking plants such as Aloe and Agave, in compositions inspired by the arid landscapes of South Africa. Adding volcanic rocks or white gravel enhances its luminous quality.