A crown of thorns plant is easy to grow indoors and out. But there are few caveats to be aware of before you add this succulent to your home.
Crown of Thorns Plant: Pros and Cons
Is crown of thorns a good plant for your home or garden? Take a look at the pros and cons before you decide, plus get expert tips on how to grow it.
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Crown of Thorns Plant Care and Growing Tips
- Common name: Crown of thorns
- Scientific name: Euphorbia milii
- Zones: 9 to 11
This thorny succulent with irritating sap can be tough to love, but the long-lasting vibrant flowers make the challenges worthwhile. Luckily, the tropical plant needs little care, so you won’t have to deal with the prickly stems very much. Crown of thorns has been widely hybridized, so keep an eye out for newer varieties with yellow, peach, pink and white blooms along with the typical red-flowering types.
Check out the top 10 colorful succulents you should grow.
What Does a Crown of Thorns Plant Look Like?
“I purchased this plant (above) on clearance. What is it?” asks Birds & Blooms reader Sandra Braddock of Santa Clarita, California.
Horticultural expert Melinda Myers says, “You are the proud owner of a crown of thorns (Euphorbia milii). It prefers bright light and well-draining soil. It tolerates low humidity, making it well suited to growing indoors. Don’t be alarmed when the plant drops its leaves. This is common and usually happens in winter.
The root system is relatively small compared to the top growth, so don’t be anxious to transplant it to a larger container. Beware of the thorns that surprise inattentive gardeners, children and pets, as well as the sticky white latex sap that can irritate the skin and eyes.”
Discover surprising facts about succulents.
Pros and Cons of Growing Crown of Thorns
Pro: Year-Round Flowers
Crown of thorns has clusters of flowers, with newer varieties boasting larger blooms. In the right growing conditions, you’ll enjoy these flowers for months or even year-round. Be sure to provide the plant with plenty of direct sunlight — at least three or four hours a day. Place it by the sunniest window you have, and move it outdoors for the summer. This plant dislikes sudden temperature changes, and reflects that by ceasing to flower. Be patient. Once it adjusts to the new setting, the flowers will return.
Con: Lots of Spines
The “thorns” in this plant’s common name are no joke. The woody stems of crown of thorns are covered in long sharp spines. It’s impossible to handle this plant without getting stuck at least once or twice, so always wear thick garden gloves, even when watering.
Pro: Easy-Care Succulent
This spiny succulent is shockingly easy to care for, indoors or out. As long as it receives enough sun and is planted in well-draining soil, it should thrive. Water when the top inch of potting soil is dry to the touch. Poke a stick an inch down into the soil and see if it comes up dry. If so, it’s time to water. Water thoroughly and let the excess drain out the bottom of the pot. Empty the saucer afterward so the roots don’t sit in the water and rot.
Con: Latex Sap
Like all euphorbias (including poinsettia), crown of thorns has copious amounts of latex in its leaves and stem. This latex can irritate your skin and even cause serious allergic reactions in some people. This offers another reason to always wear gloves when handling this plant. If you or anyone in your household has a latex allergy, pass on this plant entirely.
Pro: Grows Well Inside
A year-round flowering plant that grows well indoors is the dream of many houseplant collectors. Crown of thorns likes the same average temperatures as humans (60 to 75 degrees), but can tolerate temps as low as 50 degrees or high as 90 degrees. In zones 9B and higher, you can grow it outdoors as long as you protect it from frost, unless you regularly experiences temperatures higher than 95 degrees or so. Everyone else should find their home environment just about perfect for this bloomer.
Con: Crown of Thorns Sap Is Poisonous
Remember that latex sap? In addition to being irritating to skin, it’s poisonous if ingested. If you have kids or pets in your house, this plant may not be the right choice for you.
Next, find out if poinsettia is toxic to cats and dogs.
About the Expert
Melinda Myers is the official gardening expert for Birds & Blooms. She is a TV/radio host, author and columnist who has written more than 20 gardening books. Melinda earned a master’s degree in horticulture from the University of Wisconsin-Madison.
