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Crown of thorns

Euphorbia milii

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Crown of thorns · Euphorbia milii

Thorny stems with small bright flowers, very tolerant of heat and drought.

Care and placement

Needs full sun (at least about 4 hours), very free-draining mix and a soak-and-dry routine; tolerates heat and drought; thorny stems and toxic latex.

Draft mature dimensions

Maximum height (cm): 80 cm · Maximum spread (cm): 60 cm

Things to consider

All parts are toxic if eaten; the white latex causes contact dermatitis, stinging of skin and eyes, nausea and vomiting in people and pets (Euphorbia is listed by ASPCA as toxic to dogs, cats and horses due to irritant sap). Wear gloves and eye protection when pruning, wash hands and tools afterwards; keep from children and pets.

Unknown evidence does not mean safe. Decorative plants are not automatically edible.

Information is compiled from multiple reputable sources for reference. If you spot an error, please contact us so we can check and update it.

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How to grow and care for it

  1. Planting and pot

    Use cactus mix with perlite or coarse sand in a pot with drainage holes; a slightly snug pot promotes blooming. Thorny and toxic: wear gloves when repotting.

  2. Light

    Needs strong direct sun, at least about 4 hours daily; more sun gives more flowers, though 3–4 hours still flowers. In hot climates give midday shade. Low light drops leaves, stretches it and stops flowering.

  3. Watering

    Soak-and-dry: let the mix dry between waterings; this limits leaf drop and encourages blooms. The mix must drain freely to avoid root rot.

  4. Feeding

    Diluted low-nitrogen fertilizer (half strength) from every 2–4 weeks to monthly in spring and summer; high nitrogen gives foliage but few flowers. Reduce or stop from late autumn to early spring.

  5. Pruning

    In late spring cut just above a node to shape and branch; remove dead, weak or overgrown stems. Deadheading faded bracts triggers new flushes. Wear gloves and eye protection.

  6. Propagation

    Tip cuttings: rinse or blot the cut end to stop the sap, let it callus for several days to a week, set in dry gritty mix and water sparingly until rooted; spring and summer are best.

  7. Pests and common problems

    Mainly root rot from overwatering; no flowers from too little sun, overwatering or too much nitrogen. Mealybugs and spider mites may appear — treat with neem oil.

  8. For more flowers

    For near year-round blooms: plenty of sun (4+ hours), soak-and-dry watering, low-nitrogen feeding, a slightly snug pot, deadheading and pruning after each flush.