How to care for crown of thorns (Euphorbia milii)

Euphorbia milii · Christ plant, Christ's thorn

Crown of thorns (Euphorbia milii) — a spiny succulent shrub with thorny stems and leathery leaves; tiny flowers sit inside long-lasting red, pink or white bracts. It usually stays under 60 cm as a houseplant. Crown of thorns needs full sun. Water it about every 14 days while it grows and about every 45 days in the winter rest.

Checked against sources: November 5, 2026

Watering and repotting crown of thorns through the year

It lives indoors all year, so it has no sowing or planting dates: it grows from March to September and rests from October to February (the other way round in the southern hemisphere).

Repot it about every 36 months.

When to plant crown of thorns?

Plant or repot crown of thorns in spring, as it starts into growth; early to midsummer also works. It is a houseplant, so it has no outdoor planting date and no frost decides it: just avoid autumn and winter, when growth slows and fresh compost stays wet too long. After that, move it to a slightly larger pot about every three years, or sooner once roots circle the pot or grow through the drainage holes.

Watering in the growing and resting halves of the year: Watering and repotting crown of thorns through the year.

Sources: RHS: How to repot a plant · Penn State Extension: Repotting houseplants

Quick facts

Type	Houseplant
Latin name	Euphorbia milii
Family	Euphorbiaceae
Also called	Christ plant, Christ's thorn
Light	Full sun
Frost	does not tolerate frost
Repotting	every 36 months
Grown in	At home

Crown of thorns care by growth stage

At home

Stage	Watering	Temperature	Feeding
Growth	every 14 days	—	potassium, 14 days into the stage; potassium, 44 days into the stage; potassium, 74 days into the stage; potassium, 104 days into the stage; potassium, 134 days into the stage; potassium, 164 days into the stage
Winter rest	every 45 days	—	—

Growing notes

Light

Full sun, at least six hours of direct light a day, for example at a sunny south- or east-facing window; give it a well-lit spot over winter too.

Soil

Well-drained soil-based potting mix; RHS suggests three parts loam-based compost to one part grit.

Care

Water sparingly. Keep the compost just moist in summer and dry in winter, because it dislikes cold, wet soil and temperatures below about 2 °C (35 °F). Feed monthly while it is growing with a low-nitrogen liquid fertiliser. Leaf drop before the winter rest is normal. As a houseplant it blooms from late winter well into autumn. The milky sap irritates skin and eyes, so wear gloves, and let cuttings dry before planting them. Repot only after several years. Watch for scale insects, mealybugs, thrips, mites and grey mould.

Pests and diseases of Crown of thorns

2 problems are recorded for crown of thorns; each has a page with symptoms, treatment and prevention.

Diseases

Grey mould

Pests

Scale insects

Other plants of the Euphorbiaceae family

Crown of thorns belongs to Euphorbiaceae; 2 other plants of this family have a guide here.

Plant lists it is in

What to grow on a windowsill or balcony

Part of: Houseplants · Flowering houseplants · Houseplants for a sunny window · Houseplants that need little water

Sources

Figures checked against these sources.