How to Take Care of Crown of Thorns Plant

Find the details on how to grow crown of thorns plant, crown of thorn plant problems and to care for crown of thorns plant indoors and outdoors to get more flowers year round.

The crown of thorns (Euphorbia milii), Christ thorn or Christ plant is a flowering thorny plant. It is a spurge family Euphorbiaceae plant native to Madagascar. Some of the other plants in the purge family are Poinsettia, Castor Bean and Cassava.
Crown of thorns grows in warm climates. The crown of thorns plant is considered good luck plants, specially in India and China.

Crown of Thorns Plant, Flowers
Crown of Thorns Plant, Flowers

The crown of thorns have over 2,000 varieties. The hybrids of Euphorbia milii and Euphorbia lophogona produce flowers in clusters of brilliant blooms.

It is a popular succulent houseplant shrub having 2.5 cm long spiny stems with fleshy green leaves that grows to about 2 m tall in garden but much smaller in a pot. The new growth produces green fleshy leaves, up to 3.5 cm long and 1.5 cm broad. 

It may produce blooms throughout the year in tropical regions, elsewhere mostly in spring to summer. The flowers are small yellow, red, pink or creamy white in color.

Growing the crown of thorns plant indoors as a houseplant is easy because it adapts quickly to normal indoor environments. It can grow to a height of up to 6 feet outdoors in Madagascar, elsewhere to 2-3 feet high.

How To Care For Crown of Thorns Plant

The crown of thorns plant can be propagated from cuttings and seeds, see full details here, How to grow crown of thorns from cuttings.
Video on how to care for crown of thorns plant

how to grow and care for crown of thorns plant
how to propagate crown of thorns from cuttings

Where to Grow Crown of Thorns: Temperature

The crown of thorns thrives in warm climates with temperatures in the range15-35°C (60-95°F ), above 32ºC (90ºF) is better. In U.S. it can grow in hardiness zone 9-11. They are heat tolerant and drought resistant like a cactus. Plant your Euphorbia Millii in full sun.

Plant at a spot which receives full sun in morning. Provide some shade during hot noon in dry climates for better blooms.


  1. The Crown of Thorns plant does not need much water. Too much water or no water in hot days can kill the plant.
  2. Water only when the soil is dry 2 inch below the surface. Water until it comes out the drainage holes.
  3. Overwatering can lead to yellow leaves. The roots can rot and the plant may die, if it remains water clogged or sitting in water for a long time. So ensure that the soil should be free-draining and the container should have drainage holes. 

Fertilizer For Crown of Thorns Plan

The crown of thorns does not need much fertilizer. Feed a diluted balance solution of a balanced fertilizer (10:10:10) once a month during the growing season, spring to summer. If not blooming, then feed a fertilizer 1:2:1.

Repotting Crown of Thorns Plant

Repot the plant every 2 to 3 years in the next size of the pot in late winter or early spring. The pot should have a number of drainage holes. repot in free-draining potting mix or cactus soil for fast draining.

How To Get More Blooms on Crown of Thorns Plant

The Crown of thorns produce flowers throughout the year in tropical locations, and from late winter or early spring to autumn (fall) if grown indoors or in other locations. Crown of thorns plant not blooming? Many times, your crown of thorns may not bloom, then how to get it to bloom. The following tips will be useful to get more blooms on your crown of thorns:
  1. A crown of thorns plant will bloom best when it receives about four to six hours of direct sunlight daily. Too much sun on warmer days will scorch the flowers and change their color. So it is better to protect it from hot midday direct sunlight.
  2. If the temperature goes below 15.6°C (60°F), the plant will stop flowering. The grow lights may help to raise the temperature.
  3. If growing indoors, then place your crown of thorn plant on south facing window to get sunlight. If you do not have such a window, then use grow lights to get blooms.
  4. Too much light at night can reduce blooming. Darkness during night stimulates blooming.
  5. Proper soil mixture is also very important for crown of thorns to bloom. Use a free-draining nutrition rich potting mix. Mix some coarse river sand in the garden soil to make it free-draining and compost or cow manure for adding nutrition to it.
  6. Nitrogen rich fertilizer will grow foliage and no blooms, so feed a N:P:K fertilizer 1:2:1. Feed your plant with phosphorus rich fertilizer like bone meal, diammonium phosphate, superphosphate and seaweed solution every month during the growing month.
  7. Feed a liquid fertilizer once a month in the growing season.
  8. Remove some of the bottom leaves so that the plant directs all of its energy in growing flowers and their size.

Crown of Thorns Problems: Pests and Diseases

The Crown of Thorns can have problems of root rot, leaf spot disease, rust, powdery mildew, and southern blight, etc. if your crown of thorn plant is not growing well, you can save a dying crown of thorn plant by identifying the following problems and their treatment.
  1. Crown of Thorns Plant Leaves Turning Yellow: The yellowing of leaves may be due to lack or excess of water, frequent temperature changes, or lack of nutrients.
  2. Crown of Thorns Plant Leaves Turning Brown: Under watering and too much sun can result in dry brown edges on leaves or curly leaves. If the soil remains wet and does not dry, then the bottom part of the plant may become brown.
  3. Spots on Crown of Thorns Plant: The black or brown spots are due to either a bacterial leaf spot disease or by fungal infection due to overwatering.
  4. Crown of Thorns Plant Leaves Drop: May be a result of excessive water in soil, the leaves first become yellow and then drop. The leaves can also drop if the plant remains without water for too long. Water the plant when the top 2 inch soil becomes dry.
  5. Crown of Thorns Plant Drooping: The leaves drooping can be due to excessive water, or the soil does not drain water quickly, resulting in root rot. You can recover and save you crown of thorns plant by repotting in cactus soil, remove the rotten part and avoid overwatering.
Taking care of above problems of crown of thorns plant, you can revive and save your dying plant.

How To Prune Crown of Thorns Plant

  1. The crown of thorns is a slow growing plant so it does not need pruning for first second or third year.
  2. As a general rule, it works best to cut the stem at its point of origin to prevent stubby, unsightly branches.
  3. Prune during dry weather to prevent the risk of stem diseases.
  4. Prune the crown of thorns to remove weak, dead, or damaged branches.
  5. Prune the branches that cross other stems to make room for growth and air movement. Prune them at their point of origin.
  6. You can prune it to give it any desired size and shape. Proper pruning your crown of thorns plant will make it bushy.
  7. How to get crown of thorns to branch out: Prune the growing branches at their tips. New branches will emerge at every pruned branch, that will make your plant bushier and fuller. 

Care of Crown of Thorns In Cold Weather

  1. Crown of Thorns can tolerate extended periods of temperatures below 2ºC (35ºF) and light frost in garden beds. Below 15.6°C (60°F), the plant will stop flowering.
  2. If you have grown your crown of thorns in your garden bed, then the soil around the roots may protect the plant even in cooler temperatures, but the potted Euphorbia Millii will be susceptible to damage because of little soil to protect them.
  3. Water lightly and then cover the plant with a blanket. Remove the blanket in the morning if daytime is warm.
  4. Do not prune your crown of thorns plant in late summer, as the new growth after the pruning will be susceptible to frost damage.
  5. Do not feed your crown of thorns plant for 3 months before the expected frost time in your area, as the new growth after feeding will be susceptible to frost damage.
  6. Crown of Thorns will not tolerate temperatures below 10°C (50°F) in pots.
  7. After cold weather is over, prune any damaged stems due to frost in spring, you will soon see new growth.
  8. If growing in a pot, you can bring it indoors in the the balcony or basement.

Frozen Crown of Thorns Plant

Can crown of thorns survive a freeze?
May be yes. In spring, remove any damaged growth. In spring water very lightly and see for the new growth. After that you can feed and water your plant normally.

Toxicity of Crown of Thorns Plant

The white milky sap from damaged stems or branches is moderately poisonous and can cause skin and eye irritation on contact. It causes irritation in mouth and throat, and stomach pain and vomiting, if ingested.

Benefits of Crown of Thorns Plant

  1. The white milky sap from stems and leaves of crown of thorns plant may be used as a cure for cancer and warts, according to Chinese and Brazilian medicine.
  2. Pesticide: The crown of thorns plant is a natural way to control snails. The extracts from the plant are used to control the snail population.