Euphorbia geroldii (Gerold's Spurge)

Euphorbia geroldii, commonly known as Thornless Crown of Thorns, is an evergreen succulent shrub in the Euphorbiaceae family, native to Madagascar. It is related to the familiar Crown of Thorns, Euphorbia milii, but is distinctive for its smooth, spineless stems. The branching plant carries glossy, oval green leaves concentrated toward the ends of the shoots and can develop into a dense shrub about 3-6 ft tall. Small true flowers are surrounded by conspicuous bright red bracts, usually produced in pairs and held in clusters above the foliage. In warm conditions plants may flower repeatedly through much of the year. The combination of lush foliage, red flowers, and thornless stems makes it an attractive and relatively unusual ornamental euphorbia.

Euphorbia geroldii grows best in bright light to partial sun and warm conditions. It prefers a loose, well-drained soil or succulent mix but appreciates more regular moisture than many strongly xerophytic euphorbias; allow the surface to dry somewhat between waterings without keeping the plant excessively dry for long periods. It responds well to pruning and can be propagated from stem cuttings. This tropical species is frost sensitive and is best suited outdoors to USDA Zones 10-11 or grown as a container plant elsewhere. Like other Euphorbia, it produces irritating, toxic milky latex when damaged.