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Crown of Thorns – Euphorbia milii

Written by Hilary on November 8th, 2006

At this time of year people start thinking about Euphorbia pulcherrima commonly known as the Poinsettia.

There are, however, many other nice Euphorbias and one of them is Euphorbia milii – Crown of Thorns.

I wanted to talk about this plant because it’s not as well known as the Poinsettia, and because it can be very showy with these bright pink bracts nearly all year long.

It’s a nice little evergreen, and I grow mine as a houseplant. They can get up to 4 feet eventually with about 1 foot spread.

Bract colors can vary and come in yellow, red, and orange. They grow great in a container and are tolerant of salty soils, so if you live at the beach, you could grow this outdoors.

It tends to like very little water so let it dry out between waterings. It does well in full sun to partial shade, but mine likes it in the house in very bright light with some direct sun in the afternoon.

Do be careful around this plant though, it does have some pretty big thorns all along its stem, thus its name. As long as you’re careful you’ll not have any problems.

So if you haven’t tried one, try Crown of Thorns and give the Poinsettia a run for its money this season!


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73 Comments so far ↓

  1. Bob says:

    Like your comments. Are questions OK? I have a nice plant, in the house, in bright light, etc. It is now getting pretty rangy. I like the compactness of the one shown in your photo. Is pruning OK? How and how much? Can cuttings be rooted? How big? Will appreciate your info.

  2. Hilary says:

    Hi Bob,

    Good to hear from you, questions are always OK!

    Here are some tips I think should answer all your questions:


    Pruning is best done during cool, dry weather to lessen the risk of stem disease, so I would wait until the spring. Since you are in California however, and we’re not getting a ton of rain right now, you’re probably OK doing it now, just be careful. Since it grows so slowly you won’t have to prune it more than every 2 or 3 years, but Crown of Thorns will not only tolerate as much pruning as you want to give it, but it will actually become a much shapelier plant as a result of it. I have cut mine back to a stump in the spring and by mid-summer it is full and beautiful. Just make sure to give it a lot of light after cutting back so the new growth stays stocky and compact. To start you can take off a 1/3 up to 2/3rds of growth.

    A Word of Caution – if you don’t already know this – as a Euphorbia, Crown of Thorns will bleed white sap when cut, which can be irritating to the skin to some people (I personally have never been bothered), so you may chose to wear gloves, and be sure to keep your hands away from your face until you’ve had a chance to wash well; better safe than sorry.

    A Good Tip – When cutting, have a mister handy to mist the cut ends of the remaining plant (it will help stop the sap bleeding)


    Since Crown of Thorns is a semi-succulent shrub, you can treat it very similarly to cacti.

    Crown of Thorns is usually propagated from tip cuttings. Remove 3 inch (7.6 cm) stem tips. Place the cut end in water until the flow of sap stops. As soon as the sap stops bleeding, take it out of the water (don’t let it sit in there too long, it will rot) and allow the cuttings to dry for a 3 or 4 days. When a callus has developed, dip the ends in rotting hormone and place in a well-drained rooting mix. A good mix is a 1 : 1 : 1 ratio of sand, perlite and peat. Keep the mix slightly moist, but never wet. This Euphorbia doesn’t like a lot of water. They will be rooted in 20 to 30 days and you can plant them out.


    Crown of Thorns is drought tolerant, so when they are established, allow the top 1 inch of soil to dry out between waterings. It is very important not to over water, especially if the daytime temperatures are below 75 degrees F (23.89 C). Around the middle of May and the middle of October, apply a light complete, slow release fertilizer, like a 15-15-15.

    I think that covers all your questions. Good luck, and let me know how it goes!

  3. Janette Emlen says:

    I rooted a cutting, just like you said. This was from my great grandmother’s plant which was dying and I had trully panicked, so thank you!
    It is doing well now, and is 5.5 inches tall, with 13 healthy leaves on the top 2 inches.
    Now I am wondering — Should I cut back this cutting a little bit to encourage side growth? Or will it just naturally grow side shoots without pruning?

  4. Hilary says:

    Hi Janette!

    I’m glad you were so successful. It can make you nervous when it is a plant you really care about!

    The one problem with this plant is that it tends to develop long stems unless you prune it regularly to keep it branching out.

    I’ve had a crown of thorns plant for several years. It started as a single stem in a small pot. By taking a tip cutting, I caused it to begin branching. This plant is now nicely branched.

    You can cut these back severely (most times of the year except winter) to have them grow in more full and lush.

    I tend to cut mine back when they get too tall and they recover just fine.

    I hope this helps.


  5. Anonymous says:

    Mine hasn’t bloomed in several months. I’m in Texas, ouside of Houston. I just moved it inside due to cooler weather arriving. Can I fertilize it and get it to bloom.

  6. Anonymous says:

    I have a question about two cuttings a friend gave to me from her plant which is 35 years old. She cut these in Nov., and they have been in water ever since. They have beautiful leaves, one is even blooming, but no roots.
    Should I proceed as you have described, cut a little off the bottom, dry it out for 1-2 days, dip in rooting hormone, and plant or???
    I appreciate any help you can give me!

  7. Hilary says:

    Hi Ben,

    Good question. Since the cuttings are growing and doing well, I would treat them almost like a regular plant even though they have no roots at this time.

    I would take them out, give them a fresh cut, just as you said, and then follow the rest of the instructions as written.

    These are tough plants, and the cuttings you have sound nice and and healthy, and will do just fine.

    Have a great day!

  8. Anonymous says:

    Do you water a Crown of Thorns from the top or the bottom? Also,
    do they like to be root bound or should they have plenty of space to spread out?


  9. Hilary says:

    My crown of thorns is very tolerant. I can water if from above or below and it doesn’t matter. I do however, keep the leaves fairly dry. Even though I have never had a problem with mildew on the leaves, why tempt fate?

    As for the roots. I have a terribly rootbound crown of thorns, and another out in the garden where the roots have plenty of space, and both are doing great with healthy leaves and lots of flowers.

    They are tough plants and it really takes some effort for them not to do well!

    Hope this answers your questions.

  10. Anonymous says:

    We have just moved to Florida and planted crown of thorns in our lanai. They look beautiful. Just wondering how to fertilize them.

  11. Hilary says:


    It’s hard to see all the information sometimes, but if you read the above comments, I go over propagation, care, and maintenance tips.

    Here is it is again, hope this helps!


    Crown of Thorns is drought tolerant, so when they are established, allow the top 1 inch of soil to dry out between waterings. It is very important not to over water, especially if the daytime temperatures are below 75 degrees F (23.89 C). Around the middle of May and the middle of October, apply a light complete, slow release fertilizer, like a 15-15-15.

  12. Jean says:

    I’ve been looking for a euphorbia milii for a long time, and I finally purchased one today. However, I noticed in the store that some of the bracts look sooty with their yellow centers rotting out. All of the plants looked like this, and I chalked it up to over-watering. My question is – is this a problem I can fix, or should I return my plant post haste? Thanks for your help!

  13. Hilary says:

    Hi Jean,

    Sounds to me like you bought a sick plant.

    I would return it at once and ask the store to order you a fresh plant if they don’t have one in stock.

    No plant, when you initially buy it, should look sick or cause you to think that something is wrong with it.

    Without seeing the plant, it’s hard to say what’s wrong. The bottom line is, why should you have to fix a problem that the store started? You shouldn’t!

    Return it and start with a fresh healthy plant.

    Good luck!

  14. asfasf says:

    hi, i bought a crown of thorns from home depot and it was doing well for the first month or so. but recently, i noticed the leaves on the plant were dying one by one from bottom to top.
    i water the plant once a day in the morning…around 6-7 am it is in my balcony where it gets a good amount of sunlight everyday.

    my plant is almost completely dead!! please help!!!

  15. Anonymous says:

    Just wanted to say thanks. I was looking online to find out about how to make my crown of thorn more bushy/branched. It is quite hearty but only has three main stalks. I will try cutting it back to allow it to grow more branches. Your advice on maintaining the plant is very helpful.

    And from personal experience, when I rooted my plant from my mothers I just stuck the cuttings directly in water and they all developed great root systems. Then I later moved them to potting soil. Very easy plant to grow.

  16. Hilary says:

    Thanks so much for the note, I’m so glad you found the information helpful.

    Also, thanks for mentioning how you root your cuttings in water. It’s great to have hear about how other people succussfully work with their plants!

    One thing I have learned, there is always another way!

  17. Hilary says:

    Hi Heog,

    Well, it sounds like you are overwatering your plant.

    Crown of Thorns, is a Euphorbia and they are drought tolerant plants. They simply don’t like a lot of water.

    My advice is to stop watering everyday and allow the plant to dry out between waterings.

    In the care and maintenance section above where I give specifics, I do mention:

    Crown of Thorns is drought tolerant, so when they are established, allow the top 1 inch (2.5 cm) of soil to dry out between waterings. It is very important not to over water, especially if the daytime temperatures are below 75 degrees F (23.89 C). Around the middle of May and the middle of October, apply a light complete, slow release fertilizer, like a 15-15-15.

    For more care and maintenance tips, read the above entry addressed to Bob, I think it’s the second one from the top.

    Good question, and good luck!

  18. Sue K says:

    Hello! I hope you can help me! I inherited my mother’s 20+ year old Crown of Thorns plant when she passed away four years ago. Early this spring our cats started pulling dirt out of the pot. My husband put (what we now know were too many!) small rocks on the soil to discourage them. I kept watering as always and after a while the plant really looked terrible and we discovered it was SWIMMING in water! AUGH!!! We removed the rocks and cut way back on watering, but it looks to be dying. HELP!!!! Any advice would be sooo welcome! Thank you!!

  19. Hilary says:

    Hi Sue,

    Sounds like you are on the right track.

    Allow the soil to dry out as you have been and keep an eye on it.

    If the plant continues to look bad, you can follow the instructions I have listed above and take cuttings from your plant and start new ones.

    I understand the emotional issue at stake here, but the good news is that the new cuttings will still be the same plant that was your mother’s, you will just have more of them.

    Good luck!

  20. Anonymous says:

    I bought a Crown of Thorns 3 days ago. I have never taken care of a plant like this, so I was wondering about a couple of things. I read your care instructions, but I don’t revall anything about how much sunlight it should have. I live in central Texas, so is it okay to put outside right now?

  21. Hilary says:


    Good question! Crown of Thorns like a warmer climate, and if grown outdoors, they can get frost damage if the temperature drops below 28° F (-2° C).

    They do well with full sun, but in very hot climates like Pheonix Arizona and Central Texas, it's best to give them afternoon shade.

    Indoors, give them bright light, but not direct sun.

    Hope this helps!

  22. Linda Opferman says:

    I don’t know if this is the proper place, and if not maybe someone can point me in the right direction.
    I have a crown of thorns which I have grown from 3″ tall to its current 24 1/2′
    I has flourished in my kitchen window, but is now too tall.
    All of the flowers and leaves are on the top 1/3 of the plant, and I would like to cut it back to a more manageable size.
    I would like to know how much I can safely prune it back?
    Any help you can give me would be greatly appreciated.

    Linda O

  23. Hilary says:

    Hi Linda,

    You are in the right place and this is a good question.

    I just cut one of my Crown of Thorns back quite heavily (down to about 6 inches (15 cm) and it is doing just fine.

    There are 2 things I would do since yours is so tall:

    1. I would take cuttings as I outline in previous posts above

    2. Then I would go ahead and cut the rest of the plant back to the size and shape you want.

    I did this with one mine recently and the pruning forced new growth from the base of the plant as well as along the stems.

    It took a while, but it did grow back and is looking nice and full again.

    Good luck and let me know how it goes.

  24. Anonymous says:

    Can someone tell me if they have ever heard that the crown of thorns plant carries a cancer causing virus. I have a beautiful plant and my neighbor just told me that she read in a health magazine about this virus. Chris

  25. Hilary says:

    Hi Chris,

    I would love to know which magazine she read that in and could give me a few more specifics.

    As far as I know that is not true, and she may have mixed up the Crown of Thorns Starfish that is causing some viral problems with coral plants.

    I think you’re safe.

    The only other ornamental plant that I know of that is cancer related is Vinca (Catharanthus roseus) which has alkaloids in it that actually helps fight cancer.

    Let me know if your neighbor can give more information, because I would love to know.

    Thanks for your note!

  26. Anonymous says:

    hi hilary!
    your site has been very informative but i have to be sure before i do anything drastic. my crown of thorns is one stem only- but its tall. so if i cut it back it will have no leaves, is this ok? and will it branch out two stems from the top, or from the sides, or what? and do you know what the roots actually look like?
    thanks for your help!

  27. Anonymous says:


    I really wish I had found more information on this plant 6 months ago. I was given this plant as a present and was told that it is an indoor plant that required no sunlight and weekly feedings. It seemed to do well for a few months, but never grew any of the flowerings that I was told it should have. Plus, the leaves started falling off within the last month. So, I moved it from the cold outdoors (where it didnt have any sunlight) to my indoor family room near a window and have stopped feeding it sooooo much…we’ll see what happens. Poor thing never knew what hit it! I’d like to smack the person upside the head that told me all of that crud. Anyways, just thought I’d vent.

    Thanks for listening…Joel

  28. Hilary says:


    It’s OK to cut it back. It will produce new leaves.

    And to Joel, bummer, but I think your plant will come back! Hang in there.


  29. Edward says:

    I live in sarasota florida, I have crown of thorns in my front yardas a border. It seems that every december when these plants get more shade their leaves turn yellow orange color and fall off. Should I prune back after the leaves have fallen off ?


  30. Hilary says:

    Hi Edward,

    When temperatures drop, and I know Florida doesn’t get that cold, but during cooler temperatures, or when Crown of Thorns gets more shade, they are deciduous plants, so they will lose their leaves.

    If you want to maintain a more shrubby form, you can prune back the plant tips.

    Pruning is best done during cool, dry weather to lessen the risk of stem disease, so I would wait until the spring. By mid-summer it will have recovered and have fuller growth.

    Spring is also the best time because it will get a lot of light so the new growth stays compact

    If you like the plants as they are, you don’t need to prune them. It’s really up to you what kind of shape they have.

    Hope this helps!


  31. Debbie says:

    My Crown of Thorns is an indoor plant. I have it on a book case under bright florescent light. It must like this, because it is currently 25″ tall. I’ll be pruning it soon per your earlier instructions. However, I’m wondering if I should re-pot it as well? It’s in a 6″ pot. By the way, I water it every other week. It’s very green (lots of leaves) and has LOTS of blooms.

  32. Hilary says:

    Hi Debbie,

    Wow, sounds like you’re doing everything right and your plant is super happy! Good job.

    As for repotting, Crown of Thorns – Euphorbia milii, seldom needs repotting because of its small root system.

    I have had my Crown of Thorns for years, have never repotted it, and it is very happy.

    If for some reason you feel your plant does need repotting (ie: the roots are so dense there is no soil left, the roots are growing out of the bottom of the pot, or the root ball is being shoved upward out of the pot, etc.), use a cactus-type soil mix so the soil will drain and breathe well for the roots, which, as you know, don’t like to be in wet soil.

    Great question, and keep up the good work!

  33. Liza Singapore says:

    Hi, I’m living in hot, humid, sunny Singapore. I have 3 Euphorbia Milii Thai Poysean hybrids with really large flowers. One of them is about 1 m tall, full of flowers at the top. The problem is it’s getting too tall and I’m afraid that if I cut it back, it won’t reflower or branch out. What’s your advice on this?

  34. Anonymous says:

    Hi, I’m living in hot, humid, sunny Singapore. I have 3 Euphorbia Milii Thai Poysean hybrids with really large flowers. One of them is about 1 m tall, full of flowers at the top. The problem is it’s getting too tall and I’m afraid that if I cut it back, it won’t reflower or branch out. What’s your advice on this?

  35. Hilary says:

    Hi Liza,

    I think if you follow the same advice as given above about how to prune your Crown of Thorns, you will be just fine!

    Good luck.

  36. Pam says:

    My next door neighbor gave me a crown of thorns with 4 stalks. I repotted and the stalks are leaning over. Can I tie string around the plant to hold it together or will it hurt it? What do you suggest I use?

  37. Hilary says:

    Hi Pam,

    Sounds like you have a top-heavy plant.

    If your pot is large enough, put a stake in it – like a bamboo or thin wooden planting stake.

    Take some of the green gardening tie tape, which you can find at any garden center, and tie your crown of thorns to the stake.

    Don’t tie it tightly, just enough to give it some support and straighten it up.

    Always use something like the green tie tape for staking because it will give with the plant, whereas string will cut into the plant tissue and girdle it, which is something to be avoided.

    When more roots form, and the plants gets established and can stand on its own, you can remove the tie and the stake.

    Good luck!

  38. Anonymous says:

    hello,just want to know how safe crown of thorns in our health,coz i heard with somebody that the said thorn can cause true it is?

  39. Hilary says:


    Please read the above posts that have already discussed this.



  40. Patrick says:

    I have had my e. milii for a little over a year. I like to salvage the plants that the home improvement stores cant seem to manage, and did so with this one. It is a three stem plant with good branching on each stem. It flowered unceasingly for about a year, and then it started to mysteriously defoliate. I have not changed my cultural tactics at all since it was doing well, and am confused as to why it would decline. I tried moving it outside for a little more light, and it seemed to defoliate faster. Now I have it back inside and the defoliation has slowed, but there have been no flowers for a while, and it is slowly rejuvinating. Incedently it has a large buildup of what looks like salts on the outside of the terra cotta pot that worries me. I was hoping that you might have an idea why a thriving plant would act this way under consistently proper care.

  41. Anonymous says:

    my aunt has a beautiful large white crown of thorns. two days ago she cut a piece off for me and stuck it directly in a pot with soil…i read some of the above tips which said to let it sit out and scab over. can i still do that or is it to late?

  42. Hilary says:

    Hi Patrick,

    Well Crown of Thorns are deciduous plants, so during the winter months, or anytime the temperatures get cooler, or if the plants get too much shade, they will drop their leaves.

    Now that summer is here and temperatures are warming up, it sounds like your plant is starting to come back, which would be correct timing for a plant coming out of its dormancy stage.

    Sounds like you're doing everything right, but the salt build up does sound bad and I would start watering with filtered water if your salt levels in your water remain high.

    If you want to easily remove salt build up on your pots, read this article: Clean Your Clay Pots To Look Like New

    Hope this helps.

  43. Hilary says:

    To Anonymous,

    Since your aunt has already planted it up, I would leave it alone.

    If it looks like it is starting to rot or get soft on the cut end that is in the soil, and you'll be able to tell by keeping an eye on the base of the plant, take it out.

    Once you have taken it out, recut it, and follow the instructions as stated above for propagation.

    Depending upon the soil mix your aunt used, you might be just fine.

    Keep watching and good luck!

  44. Anonymous says:

    I am so happy to have found your site! I have 5 forms of Euphorbia milii. My largest is in a 10" pot and stands 24" tall. I was fascinated to read that you are able to prune yours so heavily. I found that if I take more than 3 or 4 cuttings the plant begins to die. It seems to "bleed to death". I will try misting the cut ends as you mentioned. My problem is that I have 1 plant that is having some problems. It develops black spots on the leaves which eventually turn yellow then brown and drop off. Is this a nutrition deficit? It is watered and fertilized the same as the others. And, one more question, I have a Thai variety. I recently discovered that they tend to have have leaves and flowers at the top portion only. Can they be forced to branch? I love the huge flowers they produce. If they can't branch, how much of the top do I remove to repot? Do I cut below the leaf growth?

    Thank you for sharing your expertice!


  45. Hilary says:

    Hi Caren,

    Sounds like overall your euphorbia are doing great. In repsonse to your question:

    "It develops black spots on the leaves which eventually turn yellow then brown and drop off. Is this a nutrition deficit?"

    This sounds like a fungal problem to me. I would spray your plant with Neem oil. For more information about Neem, and how to apply it, read our article:

    Neem Oil For Fungal and Bacterial Infections

    In response to your other questions:

    "I have a Thai variety. I recently discovered that they tend to have have leaves and flowers at the top portion only. Can they be forced to branch? If they can't branch, how much of the top do I remove to repot? Do I cut below the leaf growth?"

    There are so many large flowered Poysean hybrids (Thai varieties) that it is hard to tell what yours may do.

    The different cultivars of Poysean in Thailand could be as many as a couple of hundred. That, with the fact their growers don't differentiate among the new plants very well, can also create a problem.

    Some have large flowers well exposed and nice leaves, but don't seem to branch at all.

    Others have good branching, several flowers, and leaves that are large and floppy.

    Sounds like you have the former and because I personally have never grown one of these the best guess I can make is that even if you cut yours back, it's not going to branch properly.

    If you took a cutting and re-potted it, it would be bushy for a while before it started to grow tall and ungainly again.

    If you want a bushier plant, that is what I would do.

    When you take the cutting make sure you leave some leaves on the parent plant and get some good top growth for your cutting.

    Hope this help, and let me know how it goes.


  46. Anonymous says:


    I finally got up the nerve and "chopped" my largest plant. I did as you said and misted the cut ends. IT WORKED!!!! Thank you. The plant is now about half its original size of nearly 4 feet. The remaining plant(s) are doing extremely well. No more legginess. No more bare branches. I can hardly wait for it to bloom!

    Regarding my sickly looking plant. I wondered if it was nutrient issue. I would think if was a fungus it would have passed on to the other plants (?). I'm going to try fertilizing it a little more than the others to see if it makes a difference. Also, I do have a fertilizer I use on the outdoor flowering plants that includes a systemic fungicide. Do you think it would be okay to use it at a slightly diluted level?

    I just love e. milii. They have become so diverse with the hybrids developed since I was just a kid. I find I'm drawn to euphorbia. I am really considering "branching out" and trying some of the others that also bloom. Can you recommend one that is as easy to take care of as e. milii?

    Thanks so much for your help AND for having such a wonderful website.


  47. Anonymous says:

    By the way, I forgot to mention that I have started new plants from cuttings both by rooting in water and by rooting in soil. I have never allowed the cutting to sit for more than a day or two and have had huge success both ways.

    I mentioned in an earlier post that my largest plant was about 2 feet tall. Boy, was I wrong! It was actually closer to 4 feet tall. When I pruned it, most of the cutting were close to 2 feet long!

    I will try pruning the Thai version. I noticed today, that it is just starting to bud, so I'll wait until it has finished blooming. It needs to be transplanted and I will do it at that same time. Oh….and yes, the plant has large leaves that radiate straight out from the "trunk". It produces a few huge clusters of large flowers. I think you are probably correct when saying it is probably the first of the two forms you described.

    Thanks again….


  48. Anonymous says:

    Hilary….I guess my description of my seemingly sickly plant is incorrect. It first develops yellow spots that grow until the entire leaf is yellow, then brown, then it drops off. The plant still blooms and the flowers do not seem to be affected.

    FYI….I ordered 4 new Euphorbia milii from Glasshouse Works. They arrived yesterday. They are smallish plants in pots (not the usual naked stems). They seemed to have had a hard time – a lot of dead & dying leaves – but the stems seam to be fine. I should know by next week if they are going to make it. It was interesting in that a copy of a Certificate of Nursery Inspection, dated 04/16/09, was included in the paperwork. It states that the nursery stock was "in compliance with ……and has been found free of injurious insect and plant disease." This is the first time I have received one of these from a nursery order!

  49. Hilary says:

    Hi Caren,

    Thanks for the feeback and update. I love it when people let me know, because it helps not only me, but all the other readers of this blog.

    Sounds like your plants are doing great. Good job!

  50. Katie Steele says:

    I have had great luck over the years with crown of thorns; ceveral cultivasr (probably provind just the right amount of "neglect" along with enough light). Is it possible to grow the plants in an office setting where the primary light soufce would be fluorescent tube lighting about 3" above? I am guessing they might survive but not thrive or flower –But I am hoping you know of a variety that might work. Glad I stumbled on the site — Will be back, thanks!

  51. Hilary says:

    Hi Katie,

    If you get the light bulbs that provide both warm and cool light, giving the entire spectrum of light, your plants will be just fine.

    Thanks for stopping by!

  52. Andy M says:

    hi hilary,

    great site!

    i have a 6 year old e. milii that's doing pretty darn well. aggressive growth, lush foliage, etc etc. i keep it outside in Chicago most of the year and take it in under an HPS light for winter. two questions, though: (1) it doesnt flower much, maybe once a year with a dozen flowers, any reason why? and (2) there are a ton of odd, curly growths (looking kinda like… hard yellow brain matter) on most of the branches. ever seen this? know what it might be??


  53. Hilary says:

    Hi Andy,

    In answer to your questions:

    (1) it doesnt flower much, maybe once a year with a dozen flowers, any reason why?

    Answer: I am assuming that you are giving your plant enough sun and water, but you did not mention any fertilizer.

    Try feeding your crown of thorns a couple of times a year: once around the middle of May and again around the middle of October.

    Apply a light complete, slow release fertilizer, like a 15-15-15.

    (2) there are a ton of odd, curly growths (looking kinda like… hard yellow brain matter) on most of the branches. ever seen this? know what it might be?

    Answer: No, I have never seen that on a crown of thorns.

    Sounds like bacterial or fungal growth. Try using Neem oil which kills both types of infection.

    Use it two or three times a month as a spray on the foliage and as a soil drench.

    That should help clear it up in time.

    Hope this helps and good luck!

  54. Anonymous says:

    I was wondering if you could put decorative rocks on top of the soil in the crown of thorns plant?

  55. Hilary says:

    Sure, no problem.

    As long as you can still check the soil once in a while to see if the plant needs water, I see no problem in doing that.

    Could actually be kind of pretty if you have some good looking rocks or stones to use.


  56. Anonymous says:


    I have several potted euphorbia milii’s and they all were doing great until someone gave me one with some white silvery mold on it. It spreaded to my other beautful babies and it’s killing the flowers and leaves. What can I do to stop this. The organic sprays I got from the store does not seem to help at all.

  57. Hilary says:


    Bummer, sounds like you picked up some powdery mildew.

    One of the best treatments is to use some Neem Oil. This can be found at any nursery or home improvement center.

    You will have to use the neem oil every 7 to 10 days for a couple of months because powdery mildew is very hard to get rid of.

    Next time, try isolating any new plant given to you from the others for at least six weeks until you are sure the plant is clean of any insect or disease.

    It really helps in keeping your healthy plants from getting sick.

    Hang in there, you’ll have clean healthy plants again very soon!


  58. Carol says:

    I would like to know if you can cut some of stray growth and start a new plant from it.
    Thank you

  59. Hilary says:

    Hi Carol,

    Yes, if you read the above posts, there are detailed instructions on how to propagate crown of thorns!

    Good luck!

  60. Jana W. says:

    Just wanted to let you know that your comments have encouraged me to prune back my crown of thorn plant and to propagate it correctly! It is so scrangly! I’m glad yours was the first to pop up on Google! Can’t wait to get started!

  61. Vira Zhou, China says:

    I am from China.
    I just bought a potted plant of this flower and put it on my office’s desk.
    But today I found a terrible saying that this flower may cause cancer (nasopharyngeal carcinoma, actually) on many Chinese websites.I don’t know if it is true or just a rumor. I noticed that someone proposed the similar question above.
    Is it OK for me to put this flower on desk?Or It is better to put it outdoor?
    I would be very appreciate if you would like to help me find the truth. I need some authoritative proofs.
    Thank you very much!

    Vira zhou

  62. Hilary says:

    Hi Vira,

    I sure would like to see the websites you are talking about, but they are probably written in Chinese so I wouldn’t be able to read them.

    I personally have never heard or read anywhere that the flowers or any part of the Crown of Thorns plant (Euphorbia milii) are cancer causing.

    The only thing I have ever read is that parts of the plant are actually used to fight cancer.

    I also know that parts of the plant, because it’s a Euphorbia, can cause skin irritation on some people if the sap gets on their hands, but that’s about all.

    I’ve had the sap get on my skin and it doesn’t bother me, but that’s just me.

    I always caution anyone when working with this plant to protect their skin by wearing gloves.

    I have had my Crown of Thorns on my kitchen table for years and I am fine with that.

    I think you need to decide what makes you comfortable. If you would rather keep your plant outside and enjoy it at a distance, that’s good too.

    I personally think this plant is safe, but I always encourage people to do what they feel is best for themselves and I encourage you to do the same.

    Whatever you do, I hope you enjoy your plant!

  63. Jaren says:

    Hi Hilary,

    I have found your blog to be very informative. I have read from top to bottom. However, I do have a few questions that I would like your expert knowedge on.

    I purchased my first Euphorbia Milii this past weekend. It stands about 6 feet in height. I was shocked to find one so large. Due to the pot that it was in (damaged & cracked) the plant wasn’t in a position to stand upright without support of a wall/fencing. I decided to transfer it into a new clay pot. Since the transfer it has began to lose it’s foliage. I’m afraid that I put the plant into shock. It is also on my front porch and doesn’t get a lot of direct sunlight.

    My questions are.

    1.) Did I place the plant into shock?
    2.) Should I move the plant into direct sunlight outside or would it do best inside my home next to a window that offers direct sunlight?

    I live in Florida and the temperature is beginning to cool down here.

    Thanks in advance for your feedback and guidance. I look forward to hearing back soon.


  64. Hilary says:

    Hi Jaren,

    Well that’s quite a plant you have there!

    In answer to your questions:

    1. Any plant can experience transplant shock and what your plant is doing sure sounds like shock to me.

    Since that is the case, I would not move it into an area where it would get direct sunlight. You’ll just risk burning it and causing more damage.

    2. I think where you have it is a good place. Giving your Crown of Thorns lots of bright indirect light is the best thing for it.

    You don’t want it in the shade, it likes the light, but right now in its time of transition, direct light would not be good, it would be too stressful.

    Overall I think what you are doing is perfect.

    In time, when the plant recovers, it will be able to take some direct sun and will benefit by it, but for now, just let it get itself organized and recuperate.

    Good luck!

  65. Annette says:

    We left town during Christmas and did not leave the heat on in the house. My crown of thorns was hit hard, and although you say to wait until spring to prune, I’m temped to try cutting it back now since all of the leaves and flowers are looking seriously damaged. What do you think? (Thanks so much for all of this great help!)

  66. Wiyanna says:

    I’ve read some of the questions you have received about weather or not this plant can cause cancer. My great grandmother had a crown of thorns plant. She was given this plant as a little girl and held on to it her entire life until the day she passed away at the age of 98. She kept this plant inside in her window. She lived a very healthy life and I do not believe one bit that this plant could cause cancer. I received a clipping of that very plant that she owned from which I now have four beautiful plants. If anyone is worried about it, I suggest to always wear gloves when handling. But, do not give up on it. I know I won’t for she never did. Thank you.

  67. Cleo Gustard says:

    Hilary – Your site is more than informative! I got two cuttings of this plant – crown of thorns euphorbia milii – from the caribbean, beautiful red and salmon pink with a phyto sanitary certicate that I paid $500 for in the caribbean. they took the plants in miami customs and sent to the usda and they say the crown of thorns are phytes which they say are endangered species. can you tell me where i can get this plant to buy – Thanks Cleo

  68. Helen says:

    Thank you for your blog, I’ve learn so much. I have planted crown of thorns along side our garage wall and they are doing very well. The only problem after 6 years is that they are tall but no leaves on the bottom.
    I’ve tried pruning the longer ones but they never grow back so now they are only stumps. Should I cut it down completely to the bottom?

  69. Adina says:

    I live in Canada so have my Crown of Thorn plants planted in pots living inside. One of them is doing so well, that it grew an extra branch close to the base of the plant over the summer. This branch has become so heavy, that it has fallen over. Is it possible for me to remove this branch and use it to start another plant?

  70. Tere Wood says:

    Just discovered your blog a great help. My Crown of Thorns is an indoor plant doing great but leggy. Is the winter pruning ban for indoor too? My son lives in Tempe Az. and likes my plant would one live outside there? In sun or needs protection?

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