Euphorbia milii (yoo-FOR-bee-ah MIL-ee-eye) is a herbaceous perennial in the Euphorbiaceae family. The plant makes a perfect houseplant or an easy garden plant in the right conditions.
Euphorbia Milii, commonly named Crown of Thorns, is one of more than 1,600 species in the Euphorbia genus.
The species honors the governor of the island of Bourbon, Baron Milius, who introduced this species in 1821 in France.
Legend has it that this plant was used to form Jesus’ crown for his crucifixion, hence its common biblical names like Crown of Thorns and Christ’s Thorn.
While there is evidence that the plant existed in the Middle East before Jesus Christ, it’s more likely that another plant was used for his thorny crown.
The plant is identifiable by its sticky flowers on gray stems with long spines. It also has green leaves with red or yellow flowers.
In its native habitat in Madagasgar, Euphorbia milii can grow to a height of 6′ feet, but it will only grow to half that size as a houseplant.
If you’ve got curious pets or young children, be careful of the dangerous long spines.
Euphorbia milii goes by several common names:
- Crown of Thorns
- Christ Thorn
- Christ Plant
- Christ’s Thorn
Quick Facts On Euphorbia Milii
- Family: Euphorbiaceae
- Light: Full sun to part sun
- Temperature: 68° to 72° degrees Fahrenheit (summer)
- Water: Moderate needs
- Fertilizer: Balanced fertilizer twice a month during the growing season
- Propagation: Cuttings
- Common Problems: Scale, yellowing leaves, root crown rot
Euphorbia Milii Care
What Does The Crown Of Thorns Look Like, And How Big Does It Grow?
The Euphorbia Milii plant is a shrubby plant with gray branching stems. These branching stems are covered with sharp spines.
Narrow smooth-edged succulent leaves cover the new growth in a spiral arrangement. As the plant matures, these narrow leaves drop off, which can cause the plant to look scraggly.
However, if the plant drops all of its leaves, it’s usually due to high temperatures or insufficient water.
While the plant grows up to 6′ feet in its native habitat of Madagascar, it will generally grow to a maximum height of 3′ feet as a houseplant.
When Does The Crown Of Thorns Flower? Are The Flowers Fragrant?
Different varieties of the Euphorbia milii plant have various colored flowers, but the most common are red and yellow. They generally form clusters along the stem.
Under the right conditions, flowers bloom throughout the year.
However, Crown Of Thorns needs darkness at nighttime to initiate successful flowering. So if your plant isn’t flowering, you may need to move it to a darker area in the evening.
What Are The Lighting Needs And Temperature Requirements?
While the euphorbia milii plant is quite tolerant of full sun, it does best with full morning sun and part shade in the afternoon.
So, if you live in a hot climate, it’s a good idea to protect it from the harsh afternoon sun by providing midday shade.
In addition, afternoon shade can aid in the production of flowers.
The Crown Of Thorns prefers mild temperatures year-round, and although it can survive temperatures down to about 35° degrees Fahrenheit, it does best with mild winter temperatures.
If you live in an area with scorching hot summers, you may want to take it inside during the hottest months.
But, conversely, if you live in a harsh winter climate, you’ll want to bring your Euphorbia milii indoors before the first frost.
Thankfully, the Crown Of Thorns plant does not need high humidity to survive, so that it will do fine in heated homes during winter.
How And When To Water And Fertilize The Crown Of Thorns?
The Euphorbia milii plant has moderate water needs. Let the soil dry out before watering again to prevent overwatering and potential root rot.
Most gardeners find that fertilizing your plants twice a month during the spring and summer will encourage growth and flower production.
However, be cautious about fertilizers with boron or high levels of micronutrients. A balanced fertilizer works best for this Euphorbia species.
What Is The Best Soil For The Euphorbia Milii, And When Should You Transplant?
Like many plants, the Euphorbia Milii plant prefers well-draining soil. To ensure proper drainage, many gardeners combine commercial cactus mix with perlite, pea gravel, or sand.
While you can keep most of the Crown of thorns plants in small containers, some may overgrow their pots and need to be repotted.
It’s a good idea to repot during vigorous growth in the spring or summer.
Does The Euphorbia Milii Need Special Grooming Or Maintenance?
You can prune the Euphorbia milii plant to keep its size and shape, but you’ll want to wear gloves to avoid skin irritation.
Also, the plant’s milky sap can stick to pruning shears and knives, so be sure to clean them directly after pruning.
In addition, if enough of the milky sap gets into your eyes, it can cause temporary blindness, so eye protection is a good choice before pruning.
Lastly, be careful of the plant’s sharp thorns.
When pruning, you can remove entire branches back to the base to open up your plant or remove weak or thin branches.
How To Propagate The Crown of Thorns Plant?
You can propagate the Crown of Thorns plant by cuttings or prunings.
However, because of the milky white sap, it’s a good idea to wear gloves and eye protection when propagating.
Here’s what you need to do:
- Use pruning shears to cut a 3” to 6” inches section.
- Place the cut section in water to stop the milky sap from running excessively.
- Let the cuttings dry for a few days before placing them in small pots.
- Use a well-draining soil mixture and keep the plant barely moist.
- In about 6 to 8 weeks, your cuttings should root.
These plants can also be propagated by seed, but they rarely produce seed without hand pollination.
Euphorbia Milii Pests And Diseases
The Christ Thorn Plant is not susceptible to any particular pests or diseases but occasionally may see problems such as scale.
Other issues that may arise generally stem from overwatering, underwatering, too much sunlight, or not enough light.
If the plant is overwatered, you may experience stem or root rot. Unfortunately, it is hard to save a plant once it is experiencing root rot.
In addition, if the plant is exposed to too much direct afternoon sun, it may have problems with flower production.
Suggested Christ Thorn Plant Uses
The Christ thorn plant is relatively low-maintenance and can be grown indoors or out.
While many people keep the Christ Plant as a houseplant, it can happily live outdoors in a suitable climate. Some suggestions for landscaping use outdoors include:
- Garden bed accent piece
- Along a path, sidewalk, or walkway
- Around the mailbox
- Under low windows
Wherever you keep your plant, ensure it is not exposed to too much water or direct sunlight.
Other than that, this plant is easy to maintain and will live for years!