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How to Prune a Crown of Thorns

By Debra L Turner ; Updated September 21, 2017
Delicate blooms of crown of thorns plant
flower image by darkchoco from Fotolia.com

Crown of thorns, Euphorbia milii, is a semi-succulent shrub capable of year-round blooming. Since flowering is solely dependent upon the amount of light the plant receives, pruning won’t interfere with its bloom production. This plant benefits from and responds well to judicious pruning. Young specimens usually don’t require any pruning until their second or third years. Euphorbia is a slow grower that typically only needs to be pruned lightly every two or three years thereafter. Wait for cool, dry spring weather to minimize the possibility of disease entering open wounds.

Remove any dead, damaged or diseased stems with pruning shears.

Cut out stems that are--or threaten to become--excessively tangled or intertwined.

Prune stems wherever you think the plant could use branching. Shorten any that have become too long or unattractive. Trim back any growth that doesn’t appeal to you.

Cut particularly leggy Euphorbias back by half to promote branching of larger main stems. You can safely remove from 1/3 to 2/3 of this plant at a time. New growth with emerge from just below the cuts, resulting in a fuller plant.

Spritz the plant’s cut stems with water to staunch the copious flow of sap secretions.

Wash your hands thoroughly after handling this plant.


Things You Will Need

  • Sturdy gloves
  • Clean, sharp shears
  • Spray bottle


  • Pull on sturdy gloves to prune your crown of thorns. Not only is it heavily armed with stiff spikes, the thick, sticky, milky-looking sap can irritate the skin of sensitive individuals. The secretion also contains diterpene esters, or tumor-promoting substances. Keep your hands away from your face when handling this plant.
  • Provide crown of thorns all the bright light possible following pruning. This will ensure that the new growth remains compact, rather than becoming rangy from reaching for elusive light.

About the Author


A full-time writer since 2007, Axl J. Amistaadt is a DMS 2013 Outstanding Contributor Award recipient. He publishes online articles with major focus on pets, wildlife, gardening and fitness. He also covers parenting, juvenile science experiments, cooking and alternative/home remedies. Amistaadt has written book reviews for Work At Home Truth.