Cutting Back Crown Of Thorns: How To Prune A Crown Of Thorns Plant

By: Mary H. Dyer, Credentialed Garden Writer

Most types of crown of thorns (Euphorbia milii) have a natural, branching growth habit, so extensive crown of thorns pruning isn’t generally needed. However, some fast-growing or bushier types may benefit from pruning or thinning. Read on to learn the basics of pruning crown of thorns.

About Pruning Crown of Thorns

There are a couple of important things to know before you begin pruning crown of thorns.

First of all, this gorgeous plant was named for a reason – the thorns are wicked. You’ll need long sleeves and a pair of sturdy garden gloves for pruning crown of thorns. Even more importantly, be aware that the gooey, milky sap that oozes from a cut plant may cause severe skin irritation in some people, and it can do serious harm if it gets in your eyes.

Be careful about cutting back crown of thorns when children and pets are present because the sap contains toxic compounds. One would have to ingest a lot of the plant to have serious ill effects, but a small amount can irritate the mouth and may cause stomach upset.

Additionally, the sap will definitely stain your clothing and gum up your tools. Wear old clothes and save your expensive tools for tamer jobs. Old paring knives from a thrift store will work just fine and are easier to clean.

How to Prune a Crown of Thorns Plant

If you’re in need of trimming crown of thorns, the good news is that this is a forgiving plant and you can prune it however you like to create the desired size and shape. Two or three new branches will emerge at every pruned branch, creating a bushier, fuller plant.

As a general rule, it works best to cut the stem at its point of origin to prevent stubby, unsightly branches. Prune a crown of thorns to remove weak, dead, or damaged growth or branches that rub or cross other branches.

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Thorns primarily serve as a plant’s self-defense mechanism against predators, although they contain vascular tissue that transports fluids and nutrients. Although many plants grow thorns, notably those producing fruit, such as gooseberries, barberries and quince, rose bushes are ubiquitous with the prickly protrusions. Thorny shrubs work well when used as privacy hedging and natural landscape barriers, for they discourage animals from entering the enclosed area. Late spring and early winter is the ideal time for pruning most varieties.

Examine the shrub and identify all branches or canes that protrude over walkways and areas of foot traffic. Prune these branches back away from the walkway, using bypass hand shears that have been sterilized with bleach, to prevent injury or disturbance to passers-by.

Look over the shrub for tangled or touching branches or canes. Identify the weakest, most brittle thorny branches of the group and prune them to the branch collar.

Trim spindly canes to half their length or between 2 and 3 feet long, making the cut 1/4-inch above a healthy bud.

Open up the thorny shrub by thinning the oldest branches with the hand shears or, if larger than a couple inches, a handsaw. Cut the branches to the branch collar. If trimming a vertical-growing branch, cut to 2 to 3 inches from ground level. Thinning the shrub out allows sunlight to reach areas normally blocked from sunlight by the plant’s branches, improves aeration and promotes new growth.

Go over the shrub visually to find any branches or canes affected by disease or insects. Cut back all affected branches and canes until you reach healthy tissue. If necessary, remove entirely by cutting to the root collar.

Add branches to your compost pile after pruning as an ecologically friendly, self-sustainable means of disposable. You can also add them to other yard waste and place them in your green bin for pick up by your municipality's waste service, if available.


Succulents are commonly known for their easy-to-please nature in regards to indoor care. Even so, you should still be aware of the different needs involving keeping your Crown of Thorns alive.

The following lists all of their general requirements meant for daily care.


Soil requirements aren’t all that strenuous. The main preference that they have is for the soil to be well draining, sandy, and mixed with organic material such as humus.

Taking note of which soil you purchase will greatly impact your Crown of Thorns. These plants do not thrive when placed in a pot with the average commercial product.


There are several succulents that prefer to be placed in an area with direct sunlight. This Euphorbia is a more sensitive individual, needing plenty of light, though not for as long as one would expect.

They do like to be placed in direct sunlight, but this will cause the flowers to fade in color. Instead, your plant would do best when given lots of indirect, bright light.


The first rule of watering your Crown of Thorns is to include a good amount of drainage holes on the bottom of the pot. The needs for these plants are relatively low for a flowering plant.

This depends on the temperature that you place your Crown of Thorns in. In a warmer room, you should provide more moisture, being careful to not overwater. A good tip is to feel the inch below the soil’s surface. If it is dry, then it needs a thorough watering.


Preferring warmer temperatures, the Crown of Thorns plant is tolerant to a wide range. Even if your house gets to about 26 degrees Celsius, this Euphorbia won’t be critically impacted.

In fact, they can survive any temperature, as long as it does not exceed below 2 Degrees Celsius. This is only short a short period, though, as the leaves will start to fall off. An indoor Crown of Thorns plants should be kept right around 12 degrees Celsius for the best results.


Being a succulent, this Euphorbiaceae member is more particular about the temperature requirements. Their humidity needs are relatively low, preferring a drier living condition.

This makes them highly coveted by those with indoor plants. The Crown of Thorns does not need any additional misting, making your job all that much easier.


The Crown of Thorns plant is a fairly consistent to bloom, producing large, vibrant flowers when they do. Adding a fertilizer will do no harm to the plant as long as you keep the season in mind.

When these plants are first planted, they’ll need all the help they can get. Most choose to give them an undiluted solution during this time. After that, fertilizer can be added during the warmer months at half the recommended dose.

Regular fertilizer use should be about once a month.


You may not know this, but Euphorbia milii is a long-lasting flowering succulent, sometimes known to last up to 50 years. This rings true for those who choose to keep these plants indoors.

Propagating your Crown of Thorns may be beneficial if you have a beloved Euphorb that is exceptionally talented at producing large flowers.

These plants can be propagated through several methods such as stem cuttings, in water, and through seed germination. Out of all these techniques, cuttings seem to be the most commonly used.


These plants are known for being slow to grow to their full height, which are about 3 feet tall and 2 feet wide. When living in outdoor settings, they tend to stretch out a little more, sometimes even being a staggering 6 feet in height.

The reason for this slower growth is largely due to their large flowers. It takes a lot of energy to bloom as regularly as the Crown of Thorns does.


Although these are considered to a flowering species, the act of repotting doesn’t all in line with this category. The fact that they don’t grow quickly means that you should likely repot them every few years.

They aren’t known for getting root bound either, so owners don’t need to worry about them becoming cramped in their living space.

Watch the video: CARING for the CROWN of THORNS Euphorbia MIli Watering, Pruning, Reproduction and more!

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