Tips for Repotting a Crown of Thorns Plant

A while ago I stuck one of my Crown of Thorns, or Euphorbia Milli, into a cheap bowl from the dollar store that I drilled a hole in. I didn't have any pots on hand at the time and it was a quick fix. It's probably been a year or two in the bowl and now it's time for me to repot this Crown of Thorns. Follow this post to learn more about Crown of Thorns care, when to repot, and how to repot.

About Crown of Thorns

Crown of Thorns are succulents in the Euphorbia genus. They have proportionally large spines, lots of green leaves, and they flower prolifically. I love having flowering houseplants so I keep several of these at home. The flowers come in many colors but you mainly see red, pink, white, and yellow. The sap of the Crown of Thorns is known to be a skin irritant so be careful handling it or pruning it, you should anyway because of the thorns. You should also keep it out of reach of your pets as it is poisonous to cats and dogs.

Crown of Thorns Care

Crown of Thorns do best in bright direct light. That's how you will keep it flowering nearly year-round. I keep mine in a south-facing window and have had great results for many years. It needs well-draining potting soil and fertilization during the growing season. Water your Crown of Thorns after it has completely dried from its previous watering.

Crown of Thorns Leggy

Crown of Thorns grow in a bushy type shape when they are outdoors as mother nature intended. However, they can get leggy as houseplants. My only guess is lack of intense sunlight means it's less likely to branch out. That is no problem though. You can embrace it and grow a really tall Crown of Thorns, or you can chop it. When you chop them they sprout new branches below the cut. As I mentioned earlier though, be careful of the white sap which is a skin irritant. You definitely want some nice leather work gloves and sharp clean pruners.

Signs you Need to Repot a Crown of Thorns

Crown of Thorns typically have a pretty shallow root system and can go many years without a repot. I put mine in a very shallow bowl, which shortened the amount of time in between repotting. As you can see in the picture below, there are two big roots surfacing above the soil line in the middle of the pot. This is actually causing the Crown of Thorns on the left to lean out instead of growing vertically if the roots were able to grow downward into the pot. I will repot this in a deeper pot to help correct these issues.

Another reason you may want to repot your Crown of Thorns is if you are having watering issues. Watering issues can show up in many ways. Leaves yellowing or browning or leaves dropping rapidly. Lower leaves falling off is not an issue that is normal for a Crown of Thorns. You might also notice that the soil is drying out very quickly or that it never seems to dry out. If it's the former you might want to repot to a larger pot and if it's the latter you might want to go a size down. To take the guesswork out of watering I always recommend a cheap soil moisture meter.

How to Repot a Crown of Thorns

To prepare, you will need a clean work surface. Some leather work gloves or some kind of puncture-resistant gloves. You will need a new pot. If you're repotting to upsize, the recommendation is to use a pot one inch in diameter larger than your previous pot. If you're downsizing use a pot that is about 1 inch larger than your rootball. And please learn from me to use a pot that has some depth. I'm actually repotting to a pot that is about the same diameter but almost twice as deep.

Crown of Thorns Soil

Crown of Thorns will do fine in regular potting soil mix as long as you amend it with some perlite or other drainage enhancing materials. For Crown of Thorns, I like to use roughly 50/50 potting soil to perlite mix. You can also use soil mixes specialized for cacti or succulents.

Steps for Repotting Crown of Thorns

Put on your gloves, and you probably want to wear long sleeves as well. Grab your new pot and prefill it with your Crown of Thorns soil mix. You want to fill it to about the height you want the root ball to sit. Next, carefully remove your Crown of Thorns from its old pot. This should be fairly easy because they do not have aggressive roots. Next, you want to examine the root ball and clean any old soil off the roots that is easy to remove. As you can see, most of the roots are really fine and small. Check for mushy or discolored roots. If you have them, you need to trim them away with a clean sterile knife before you repot.

Finally, you place the Crown of Thorns into its new pot and backfill the soil mix around the root ball. You also want to cover the roots on the top to prevent the roots from drying out, but don't put too much soil up around the stems. It's best to try and wait a couple of days to water your Crown of Thorns after repotting to minimize additional shock.

Have any questions? Put them in the comments.