Does it need full sun?

Yes, it thrives in bright, direct sunlight.

Plant guide

Crown of Thorns.

Euphorbia milii

Pronounced yoo-FOR-bee-uh MIL-ee-eye

Also known as Christ's-plant, Christ's-thorn, Christplant, Crown of thorns, Christ plant, Christ thorn, crown-of-thorns

The Crown of Thorns is a sturdy succulent shrub known for its woody stems and vibrant, long lasting bracts. It thrives in sunny spots and handles dry conditions quite well. You will love how its cheerful blooms add color to your home throughout the year.

Another photo of Crown of Thorns — Photo by Robert H. Wardell (CC0) via gbif

At a glance

Care level: Easy
Plant type: Succulent shrub
Light: Full sun
Indoor light: Direct sun
Water: Every 10 to 21 days
Mature size: 60 to 90 cm
Growth rate: Medium
Hardiness: USDA 9 to 11
Bloom time: Year round in warm climates

Care

Provide plenty of direct sunlight to encourage consistent blooming. Allow the soil to dry out significantly between waterings to prevent root rot. Wear gloves when handling this plant to avoid contact with the irritating milky sap.

Watering: Water thoroughly only when the top half of the soil is completely dry.
Feeding: Use a balanced liquid fertilizer diluted to half strength during the growing season.
Pruning: Trim back long stems in late winter to maintain a compact shape.
Repotting: Repot only when the plant becomes root bound in its current container.
Soil: Well draining cactus mix
Soil pH: 6.0 to 7.5
Temperature: 10 to 30°C
Humidity: 40 to 60%
Drought tolerance: High
Lifespan: Perennial, typically 10 plus years
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes.
Water running straight through the pot without soaking in.
Stunted growth during the active season.

Safety

People: All parts of the plant contain a milky sap that is highly irritating to the skin and eyes and toxic if swallowed.
Pets: This plant is toxic to cats and dogs if ingested and its sap can cause skin irritation.
Children: Keep this plant well out of reach of children due to its sharp spines and toxic sap.
Contact allergens: The milky latex sap can cause severe contact dermatitis or blistering on sensitive skin.
Airborne allergens: There are no notable respiratory allergens associated with this plant.
Edibility: The plant is toxic if ingested and should never be consumed.

How to identify it

Sharp, woody spines along stems
Bright, colorful petal like bracts
Small, oval shaped green leaves
Milky white sap when cut

Height: 0.3 to 1.8m
Spread: 0.3 to 0.9m
Leaves: green, evergreen
Flowers: red, pink, yellow, white, 1 to 2cm

Problems to watch for

MealybugsCommon
Root RotCommon
Fungus GnatsUncommon
Leaf DropUncommon
Scale InsectsUncommon
Spider MitesUncommon

By symptom

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Growing it

Propagation: cuttings
When to plant: spring, summer
Overwintering: Move indoors before the first frost. Keep in a bright window and reduce watering significantly during the cooler months.
In containers: It is an excellent container plant, provided the pot has drainage holes and is at least 20 cm wide.

Stem Cuttings

1. Wear gloves to protect against sap and spines.
2. Take a 10 cm cutting from a healthy stem.
3. Rinse the cut end in water to stop the sap flow.
4. Let the cutting callous for a few days in a dry spot.
5. Plant in well draining succulent soil.

Group this plant with other drought tolerant succulents to ensure they all receive proper watering cycles.

Grows well with

Jade Plant — They share similar requirements for bright light and infrequent watering.
Aloe Vera — This succulent also enjoys dry, sunny conditions.

Similar species

Poinsettia — It is a related species also known for its colorful bracts.

Science

Family: Euphorbiaceae
Genus: Euphorbia
Order: Malpighiales
Class: Magnoliopsida
Native range: Madagascar
Conservation: Not currently of conservation concern.

It grows in rocky, arid environments where its succulent stems store water for dry periods.

Value to wildlife: nectar source
Pollinators: bees, butterflies
Uses: ornamental houseplant, container specimen, warm climate hedge

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Soil reaction: 6/9
Nutrients: 3/9
Salinity: 2/9
Light: 8/9
Temperature: 8/9
Moisture: 3/9

Taxonomy resolved against GBIF.

Questions people ask

Does it need full sun?: Yes, it thrives in bright, direct sunlight.
How often should I water it?: Allow the soil to dry out significantly between waterings.

Where the name comes from

The specific epithet milii honors Baron Milius, who introduced the plant to France. The common name refers to the legend that it was used for the Crown of Thorns.

Good to know

It is a succulent shrub from Madagascar.
The colorful parts are actually bracts, not true petals.
It can bloom almost continuously with enough light.
The stems are covered in sharp, woody spines.

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This guide was generated with AI and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.