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Caring for Euphorbia Geroldii: Thornless Crown of Thorns!

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Do you like Crown of Thorns, but really don’t care for, well…the thorns? If so, Euphorbia geroldii, also known as Thornless Crown of Thorns or Gerald’s Spurge, is a fantastic option! It is much harder to find than it’s thorny relative Euphorbia milii, but is well worth it!

Threatened by habitat loss in its native Madagascar, I feel a special duty to grow this plant and do my part to aid in conservation. Fortunately, this plant has proven to be very tough and resilient indoors!

euphorbia-geroldii

After living with this plant for several months, I realized several things that I love about this plant:

  • It is in almost constant bloom! The bright red flowers with yellow centers are a welcome sight throughout the year.
  • It is a relatively quick grower.
  • It can take some abuse with drought and bounce back quite nicely!
  • It has beautiful, glossy leaves.

Of course to have a nice looking plant, let’s take a look at how to care for this unusual beauty.

euphorbia-geroldii

Thornless Crown of Thorns Care Tips

Here are some care tips, and I also go into pruning and propagation near the end of this post.

LIGHT

Like any Eurphorbia, give your plant plenty of direct sunshine indoors. Place your plant in a window that gets at least a few hours of direct sun or more.

Northern exposure windows would not be appropriate for this plant as there is no direct sun there. Eastern, Western, or better yet…Southern exposure windows would be best!

My own plant grows right in front of an an Eastern facing window. It even grew and flowered throughout our dark Ohio winters!

Keep in mind that you will get fuller plants when you give your plants more direct sun indoors.

WATERING

Allow your plant’s soil to dry out completely, and then water thoroughly. I take my plant to the sink, soak the soil thoroughly, allow the excess water to drain completely, and back to the window it goes.

Don’t wait too long after the soil has dried out completely, because you’ll notice that your entire plant will wilt. I’ve done this accidentally (more than once…) because I have so many plants and it’s hard to keep track sometimes!

If you notice your plant is wilted, and your soil is bone dry, immediately take it to your sink. You’ll have to put in a little more effort at this point.

Soil that has gone dry for a long time is sometimes very hard to “re-wet.” When you water your plant, you’ll notice that most of the water will run right through.

Repeatedly water a few times in a row until the soil is moistened again, and try not to allow it to get to that point again. If you haven’t waited too long, your plant will bounce back!

On the contrary…don’t even think about watering again until your soil has dried out pretty well. Never let your Euphorbia sit in water, whether there is water in its saucer or inside its cache pot, or it will rot.

And always make sure your pot has a drainage hole!

thornless-crown-of-thorns

SOIL

These plants can not tolerate wet soil, or poorly draining soil. Be sure to use a potting mix that drains very freely.

Many people have their own special mixes and you can use many different things, but for all my succulents or semi-succulent plants, I recommend the following mix (easily available on Amazon):

2 parts Espoma Organic Cactus mix to 1 part Bonsai Jack 1/4″ pumice.

This creates a beautifully drained potting mix that you’ll love (and your plant will too)!

FERTILIZING

The International Euphorbia Society recommends regular, but light, fertilizing throughout the growing season. Use a low-nitrogen fertilizer if you can.

Keep in mind that when you repot a plant, if you are using a prepackaged soil mix, they often have fertilizer mixed into it (read the label to be sure). Over time, especially if you don’t repot often, these nutrients in the soil will be quickly depleted.

I recommend using the 2-7-7 Schultz Cactus Plus fertilizer for all your Euphorbias and other succulents and cacti.

PRUNING AND PROPAGATION

At one point, I moved my plant under grow lights in my basement. It made it easy to forget about (out of sight, out of mind…) so it suffered quite a bit and dropped many leaves.

Luckily, I’ve found that this is a very resilient plant. I took the opportunity to take tip cuttings to propagate, and I then cut the plant back very hard.

Here is the before photo.

euphorbia-geroldii-pruning

I cut it back pretty hard, resulting in this:

euphorbia-geroldii-pruning

I wasn’t sure how it would respond to a hard pruning, but 3 weeks later, the entire plant was starting to grow again.

euphorbia-geroldii-pruning

I re-homed the plant into my new greenhouse, gave it a larger pot, and I also took the opportunity to propagate more plants. I took tip cuttings from the plant.

euphorbia-geroldii-propagation

Like any Euphorbia, when you make any cuttings, the plant will ooze a milky sap. Be careful not to get it on your hands. You may ever want to wear gloves when handling the cuttings.

Allow the cuttings to air dry for a few hours, and then simply insert them into moist potting mix in order to root. I added some pumice to a cactus/succulent mix (about 1 part pumice and 2 parts potting mix).

euphorbia-geroldii-propagation

All of the cuttings above rooted and started growing pretty readily inside my greenhouse.

BUY EUPHORBIA GEROLDII ONLINE

Looking to purchase a Euphorbia geroldii? One of my favorite and most convenient one-stop-shops to buy practically any plant is Etsy. Check out the Euphorbia geroldii selection (link to Etsy) today!

Here is a photo of a plant growing outside so you can get an idea of how big these can get:

Euphorbia geroldii at the United States Botanic Garden in Washington D.C. Photo credit: Don McCulley, CC BY-SA 4.0

That’s about it! I hope you’ve enjoyed this post on Euphorbia geroldii and please comment below with any questions or anything else you’d like to share!

Please do me a favor and share this post to social media because it will help me spread the Ohio Tropics houseplant care tips to the masses! Also, check out my shop on Amazon for all your houseplant care needs:

OHIO TROPICS PLANT CARE STOREFRONT

Sita Perez

Thursday 26th of May 2022

Hi i have a thornless gerroldii and its doing great with partial sun and shade. With the florida humid and hot sun I am not quite sure if i should let it get more sun etc. Pls help. thanks

Raffaele

Thursday 26th of May 2022

If you're happy with how your plant looks where it is at, leave it there :-) You may be best to leave it in partial sun only where you live.

Mary

Monday 2nd of November 2020

Hi! I just moved into a new house and there are several Potted thornless crown of thorns around the exterior. I want to keep them healthy but they are getting quite large! Is it ok to prune them back, and if so, when and how? I’m not a gardener (yet) but am aspiring! So the simpler the explanations the better ?

Raffaele

Monday 2nd of November 2020

HI Mary, yes absolutely! Where do you live?