Euphorbia milii (Crown of Thorns)

Scientific Name

Euphorbia milii Des Moul.

Common Name(s)

Crown of Thorns, Christ Plant, Christ Thorns, Siamese Lucky Plant

Synonym(s)

Euphorbia bojeri, Euphorbia breonii, Euphorbia milii var. breonii, Euphorbia splendens f. breonii, Euphorbia splendens var. breonii

Scientific Classification

Family: Euphorbiaceae
Subfamily: Euphorbioideae
Tribe: Euphorbieae
Subtribe: Euphorbiinae
Genus: Euphorbia

Origin

This species is native to Madagascar.

Description

Euphorbia milii is a succulent shrub with many woody, branched, and densely spiny stems. It grows up to 6 feet (1.8 m) tall. Stems are grayish-brown, obscurely 3- to 5-angled, and up to 3 feet (90 cm) long. Spines are gray, sharp, and up to 1 inch (2.5 cm) long. Leaves are bright green, egg-shaped with the narrow end at the base, up to 2 inches (5 cm) long and 0.7 inches (1.8 cm) wide. They drop as they age and are clustered mainly at the branch tips. Flowers are tiny, yellow to greenish-yellow, enclosed within exceptionally showy, long-lasting, petal-like bracts which are up to 0.5 inches (1.2 cm) across and usually bright red. The plant produces flowers all year round but primarily in spring and summer.

The common name "Crown of Thorns" refers to the belief that the crown of thorns Jesus Christ was forced to wear at his crucifixion was made from stems of this plant.

The specific epithet "milii" honors Baron Milius, once Governor of Réunion (formerly known as Bourbon), who reportedly introduced this species into cultivation in France in 1821.

How to Grow and Care for Euphorbia milii

Light: This succulent is a sun lover. Place your indoor E. milii in a sunny window. From spring to fall, you may place the pot on the balcony or in the garden. Increase sun exposure gradually to prevent sunburn.

Soil: E. milii requires well-drained soil. Use a commercial mixture formulated for succulents, or make your own potting mix.

Hardiness: High summer temperatures are not a problem, but low winter temperatures can damage or kill your plant. E. milii can withstand temperatures as low as 25 to 50 °F (-3.9 to 10 °C), USDA hardiness zones 9b to 11b.

Watering: From spring to fall, water when the top inch (2.5 cm) of soil feels dry. Reduce watering in winter. Give it just enough water to prevent wilting. The best time of the day to water your E. milii in the warm season is the evening.

Fertilizing: Plants in a pot need regular feeding. Apply a balanced fertilizer in a 10-10-10 NPK formulation, diluted to 1/4 strength once a week during the growing season.

Repotting: E. milii will benefit from repotting, but it does not need to be repotted every year. When your plant is outgrowing its pot, it is time to repot it in a larger pot and give it a fresh potting mix. The repotting is best done in early spring, at the beginning of the growing season. Wear gloves, protective clothing, and appropriate eye protection when repotting this succulent.

Propagation: The easiest and fastest method of propagation for this plant is by using cuttings. It can also be grown from seeds, but it can be difficult to germinate, even hard to find. The best time to take cuttings is in spring or summer. Sow the seeds in spring.

Learn more at How to Grow and Care for Euphorbia.

Toxicity of Euphorbia milii

E. milii produces a white milky sap that is toxic and can cause irritation to the skin and eyes. It is best to keep your plant away from children and pets.

Varieties, Forms, and Cultivars of Euphorbia milii

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