1050 Euphorbia miliiCommon Names: crown of thorns, Christ plant, Christ thorns Family: Euphorbiaceae (spurge Family)
Crown of thorns is a bushy, very spiny, semi-succculent shrub that gets about 3 ft (1 m) in height, with a spread around 2 ft (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. The plant is sometimes completely leafless. The well named crown of thorns is armed with half inch (13 mm) vicious black thorns all over the stems and branches. In subtropical climates, crown of thorns bears tiny yellow-green flowers surrounded by two showy bright red bracts in spring and summer. In tropical climates, it blooms in cycles following rain throughout the year. Like the other members of the genus, Euphorbia milii oozes milky sap from bruised or broken stems and leaves. All euphorbs have a three-lobed fruit that splits apart when ripe, but crown of thorns rarely fruits in cultivation. Several named cultivars and varieties are noteworthy for their different colored bracts (pink, yellow, white, orange) and/or different growth habits. This species also has been hybridized with other euphorbs, resulting in cultivars with larger and flashier bracts.
Euphorbia milii is native to the island nation of Madagascar.
CultureCrown of thorns is a slow grower that thrives on poor sandy, well drained soils, and is moderately tolerant of salt spray and salty soils. Light: Crown of thorns likes full sun, but will survive in part shade. Moisture: Although it is very tolerant of dry conditions, regular watering of crown of thorns will keep it from dropping so many leaves and coax it to bloom more. Hardiness: USDA Zones 8 - 11. Propagation: Although it is very tolerant of dry conditions, regular watering of crown of thorns will keep it from dropping so many leaves and coax it to bloom more.
Crown of thorns is grown for its long lasting, colorful petal-like bracts which surround inconspicuous little flowers. Although often grown in pots on the patio, this thorny succulent is perfect for rock gardens and sunny borders. Crown of thorns is salt tolerant and often used in frostfree coastal areas, even quite near the sea. As a low growing hedge, crown of thorns makes a formidable barrier for low growing trespassers.
Euphorbia is a huge genus with over 2000 named species, including annuals, herbaceous perennials, shrubs, trees, and lots of cactus-like succulents, found in almost every corner of the world. If the flowers of all those species weren't so strikingly similar in anatomical structure, botanists would have split the genus into several different genera. Euphorbia flowers always have only one stigma (the female part that receives pollen) and one stamen (the male part that releases the pollen). The much adored poinsettia is a euphorb (Euphorbia pulcherrima).
Apparently all parts of most all Euphorbs are poisonous if ingested, and the milky sap can be a skin irritant.
Steve Christman 7/3/07; updated 1/6/11