Euphorbia milii

crown of thorns


Euphorbia milii

Des Moul. 1826

pronounced: yoo-FOR-bee-uh MILL-ee-eye

(Euphorbiaceae — the spurge family)


common names: crown of thorns, Christ plant

Both the genus and family names are derived from the name of Euphorbus, Greek physician to Juba II, King of Numidia from 52 to 53 BC. Pliny the Elder, writing in his Naturalis Historia in about 77 AD, describes how the king found a plant growing on Mount Atlas which he named euphorbia in honour of his physician. The word itself comes from two Greek words, ευ (eu), well, and φερβω (pherbo), to feed or nourish, so the good doctor’s name means ‘well-nourished, or fat’, and may have been a nickname; milii is for Baron Milius, the governor of Île Bourbon, present-day Île de la Réunion (Reunion Island). He introduced this species into France in 1821.

The common name refers to the legend that the crown of thorns that was worn by Christ at his Crucifixion was made from the stems of this plant. Substantial evidence exists that the species, native to Madagascar, was taken to the Middle East before the time of Christ. I am sure, however, that the legend is apocryphal. With the amount of tacky sap it exudes, constructing a crown of thorns from this plant would be a very messy affair!

Crown of Thorns is a very spiny, semi-succulent plant that grows to about 1 m in height, with a spread of around 60 cm. It has tough, leathery, bright green leaves on slender fleshy stems, but the leaves often drop off on all but the youngest stems, and the plant is sometimes completely leafless. The plant is well-named, as it is armed with vicious black thorns, up to 3 cm long, all over the stems and branches. It bears tiny yellow-green flowers surrounded by two showy bright red bracts. Like the other members of the genus, Euphorbia milii oozes milky sap from bruised or broken stems and leaves. The leaves are obovate, up to 8 or 9 cm long and about 3 cm broad.

All euphorbia have a three-lobed fruit that splits apart when ripe, but Euphorbis milii rarely fruits in cultivation.

Several named cultivars and varieties are noteworthy for their different coloured bracts (pink, yellow, white, orange). This species has also been hybridized with other euphorbia, resulting in hybrids with larger and flashier bracts.

Propagation is by cuttings taken in spring or summer. The cut end should be dipped in warm water for a few minutes to stop the bleeding, and then allowed to dry for a few days and form a callus before planting in barely damp sand. The plant is often grown in pots on patios, but it is also a good plant for rock gardens and borders. It will also make a good (and impenetrable) hedge. When grown in close proximity to other plants, it will sometimes scramble over them, helped by its thorns.

dangerous 2All parts of the plant seem to be poisonous if ingested, and the sap can irritate some skins; but I am told that the sap is used as a folk remedy in Brazil for the removal of warts.


Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.


Photographs taken in Picnic Bay 2008
Page last updated 28th December 2018