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How to Grow and Care for a Crown of Thorns Plant

crown of thorn plant

Wagner Campelo

Not all plants are easy to take care of, but even with a name like the crown of thorns (which sounds pretty intense), this plant is thankfully pretty forgiving. Despite having a thorny stem, the crown of thorns plant boasts beautiful blooms that can last year-round in some cases. And, according to folklore in Thailand, the more flowers your plant has, the more luck you'll have.

The plant is actually native to Madagascar, which explains why it can survive in dry, bright conditions. At home, be sure to place it in a sunny window where it gets plenty of light. Plan to water it about once a week, but don't fret if you forget—this plant can take a skipped watering or two.

If you're a big fan of succulents, the crown of thorns is a great plant for you. Despite looking like a regular flowering plant, it's actually part of the succulent family. Thick, fleshy leaves help the plant store water, and they also will let you know when it's thirsty. If you're interested in growing your own crown of thorns plant, keep reading.

  • Botanical Name: Euphorbia milii
  • Common Name: Crown of thorns, crown-of-thorns, Christ plant, Christ thorn
  • Plant Type: Succulent 
  • Mature Size: 3-6 ft. tall outdoors, 2 ft. tall indoors
  • Sun Exposure: Full sun
  • Soil Type: Well-drained potting mix
  • Soil pH: Below 7.0

Crown of Thorns Plant Care

Thankfully, the crown of thorns plant is pretty easy to grow indoors, but it definitely thrives outdoors in hot, dry climates. It's built to store water for when it needs it, like many other succulents, so it can withstand hot summers and periods of time without rain.

However, when indoors, it can actually flower year-round thanks to the milder conditions. Make sure you set it near a window that receives direct light (think three to four hours of intense sun a day) and don't overwater it. The key is allowing the plant to dry out on the first inch or two between waterings. When it does need a drink, water it until water runs out of the drainage hole. If you have a tray beneath the plant, empty it so the roots don't sit in water. Then, you can wait until the top couple of inches are dry again before watering.

That said, make sure you use a well-draining soil mix that won't hold on to too much water. A standard succulent or desert soil mix from the hardware store is fine, just make sure it has some sand or other draining medium in it. If you do end up going with a regular potting mix, water your plant a little less often. Typical houseplant soils will hold on to moisture for longer, so you won't need to give it a drink as often.

crown of thorns plant

Simon McGill

Best Growing Conditions for Crown of Thorns Plants

As a native plant to Madagascar, the crown of thorns plant really loves the sun. Setting it in a south-facing window or adding a grow light to a lower-light area will help the plant create the energy it needs and help it photosynthesize more easily. It can tolerate bright-indirect light, but this may stunt the growth of the plant some.

While it adapts well to temperatures indoors, try to place it somewhere where it won't ever dip below 50 degrees Fahrenheit or go above 90 degrees Fahrenheit. That's a big difference, but the plant can't tolerate winter-like conditions or extreme, desert-like heat.

Every couple of years, you may need to repot your plant. Be sure to wear gloves as the thorns are pretty large and will prick you if you're not careful. If the stem is cut, a sap will ooze out, and it will irritate skin. Also be sure to keep your pets away from this plant, as it is toxic. While repotting, put the plant in a planter that's one or two inches larger than the one it was in, as anything larger could shock the plant. You don't want to give it too much room at first.

How to Propagate Your Crown of Thorns Plant

The crown of thorns plant is pretty easy to propagate. Like most succulents, you can take a tip cutting and grow it from there. Using clean shears or a blade (and while wearing gloves), remove the top part of the stem and some leaves. It will drip sap, so be sure to dip the wet end into a bowl of warm water to stop it from oozing. Lay the cutting out to callus over for a few days, and then stick the cutting into soil, waiting for it to root. Water it occasionally, but be careful to not overwater.

Common Growing Problems

Beginner plant parents (and experienced green thumbs) will appreciate that this toxic plant tends to ward off pests and disease. It does, however, still have some issues with common houseplant pests like mealy bugs, scale, and thrips. Be on the lookout for small, white bugs or web-like structures on the plants, which may be a sign of pests moving in.

The crown of thorns is also susceptible to root rot. Be sure to take care when watering, allowing the soil to dry out completely between watering and making sure the plant never sits in water for any length of time. Fungal disease is also a possibility, and it often shows up as spotty leaves or a moldy-looking "growth."

Potting and Repotting

Like many other houseplants, the crown of thorns only needs to be repotted every couple of years or so. While wearing gloves, gently remove the plant from its current pot, loosening the roots if need be. Place it into a planter one or two inches larger in diameter with fresh cactus soil, and give it a good water. Then, all that's left to do is watch your plant thrive!