Crown of Thorns Plant (Euphorbia Milii) Indoor Care Guide

The Crown of Thorns Plant (Euphorbia milii) is a broadleaf evergreen semi-succulent shrub and a member of a large Euphorbia genus. It is native to Madagascar and grows in tropical climates worldwide. It’s quite popular as a houseplant since it requires little care and thrives indoors.

Historically, the iconic Christ’s crown of thorns is believed to be made using this plant, hence the name “Crown of Thorns Plant.” It is also referred to as “Christ Plant” and “Christ Thorn” for the same reasons. 

The real flowers are inconspicuous but are surrounded by showy bracts varying in color. These bracts, called cyathia, are long-lasting and incredibly colorful. These are often yellow or red and what most laymen refer to as the flowers on this plant. They bloom from spring to summer, but they can flower year-round if conditions are right.

The stem is thick with sharp, black spikes about an inch long. The stem and the fleshy green leaves store water like a succulent. Be careful when handling, as they can easily pierce the skin. 

Crown of Thorns Plant Main Characteristics

Common Name	Crown of Thorns, Christ Plant, Christ Thorn
Botanical Name	Euphorbia milii
Family	Euphorbiaceae
Genus	Euphorbia
Type	Broadleaf evergreen
Native Range	Madagascar
Common Cultivars	Euphorbia milii var. splendens
USDA Hardiness Zones	9 to 11
Mature Size	Height: 3-6 feet; Spread: 1-3 feet
Bloom Time	Seasonal
Foliage	Evergreen
Propagation methods	by seeds, by tip cuttings
Sun	Full sun
Soil	Well-drained
Toxicity	Moderately Toxic

Euphorbia Milii Care

Euphorbia milii is a hardy plant. It can survive extremely unfavorable conditions and still come out looking lush and colorful. But that doesn’t mean it won’t benefit from a caring hand. So here’s what you need to do.

Light and Location

Crown of Thorns plant prefers direct full sun. Therefore, place it in a sunny location, preferably on a windowsill or even on the porch. But in hot summer months, some shade from the harsh afternoon sunlight is appreciated.

Watering

Crown of Thorns plants need regular watering, but too much water will cause them to wilt and die. This plant needs fast-draining soils that don’t retain moisture. Ensure the soil dries out before the next watering session and lessen the frequency drastically come winter. 

Temperature

This plant wants a temperate, warm environment to grow and thrive. They prefer temperatures between 55 and 75 degrees Fahrenheit. Although they are hardy to 35 degrees, any lower, and the plant begins to suffer.

Humidity

Humidity-wise, the requirements are not high. They do best in 30-60% humidity, easily achievable even in dry regions. Don’t try to mist the leaves or increase moisture levels if not needed.

Fertilizer

This plant wants fertilization monthly during their active growing season with a general-purpose fertilizer. Feeding more often will cause the plant to become too leggy and will not produce as many flowers. Use a balanced fertilizer specifically designed for flowering plants.

Propagating Euphorbia milii

You can propagate Euphorbia milii from tip cuttings but let sap dry before placing the cutting in a growing medium.

1. Cut the apex of a healthy stem with a lush crown of bracts.
2. Remove the bottom leaves and insert the stem into moist soil (after waiting for the sap to dry).
3. Keep the soil moist and place the container somewhere sunny and warm.
4. The plant will grow roots and new shoots from the cut end of the stem.

You can also propagate these plants by seeds, but seeds are rarely seen in indoor plants, making them impractical and tedious. Propagation by tip cuttings is the easier and faster way. 

Potting and Repotting Euphorbia milii

When potting or repotting a Crown of Thorns plant, it’s essential to use soil that drains well. A potting mix high in sharp sand or gravel will work well, and you can also add a little bit of perlite or vermiculite to help with drainage. Use a cactus mix as a base and add rich organic material.

These plants don’t like to be wet, so make sure the soil can dry out quickly after watering. Well-drained potting soils help with that, but drainage holes are a must.

Don’t repot unless you need to; these plants want to be slightly rootbound. Wait for the roots to spill over and get overcrowded before getting a new pot. When you do, make sure to use a pot that is only slightly larger than the current pot. 

Common Pests

Mealybugs, scale insects, thrips, and spider mites are the most common pests of the Crown of Thorns plant. They can inhibit its growth, damage it, and even cause it to die. Use horticultural oils if the problem isn’t severe; insecticide if it is.

Crown of Thorns Plant (Euphorbia Milii) Care Guide (Video)

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