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|
|Common Cultivars||Euphorbia milii var. splendens|
|USDA Hardiness Zones||9 to 11|
|Mature Size||Height: 3-6 feet; Spread: 1-3 feet|
|Propagation methods||by seeds, by tip cuttings|
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.
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.
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-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.
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.
- Cut the apex of a healthy stem with a lush crown of bracts.
- Remove the bottom leaves and insert the stem into moist soil (after waiting for the sap to dry).
- Keep the soil moist and place the container somewhere sunny and warm.
- 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.
The sap of Euphorbia milii is moderately toxic and can cause skin and eye irritation if it comes in contact. The sharp spikes on the stem are also a hazard; handle with gloves. Place the plant out of reach of children and pets.
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)
How to propagate Euphorbia milii?
Euphorbia milii is easy to propagate by tip cuttings. You can also propagate it by seeds, but seeds are rarely available in the market. Remember to allow the cutting to callus over before planting and handle with gloves.
How to care for Euphorbia milii?
This plant needs full sun to thrive. Pick a spot that gets a lot of sun throughout the day. Water it frequently in the growing season and less so in the winter. Ensure proper drainage. Try to keep temperatures between 55 and 75 degrees Fahrenheit.