Crown of thorns (Euphorbia), appropriately named for its spiky thorns, is a desert plant that will produce stunning blooms in shades of red, yellow, pink and white from summer to fall, as long as it's exposed to plenty of sunlight and warmth. In hot climates, crown of thorns can be grown outdoors. Otherwise, plant crown of thorns in a container and bring it in when the temperature drops below 55 degrees Fahrenheit. Propagate crown of thorns by taking a stem cutting.
Cut a few stems from the top portion of a healthy crown of thorns plant. Use a new razor blade or a sharp knife that has been wiped with rubbing alcohol. Strip off all but the top two or three leaves.
Dip the cut ends of the crown of thorns stems in powdered rooting hormone. Put the stems on a paper towel or paper plate and set them aside in low light for one to two days, until the cut end forms a callus.
Fill a planting container with a mixture of clean, coarse sand and commercial potting mix, and dampen the potting mixture slightly. Be sure the planting container has a drainage hole in the bottom.
Plant the crown of thorns stem cuttings in the container with the leaves above the soil. Set the container in a shady spot and keep the soil barely damp. Be careful not to over water, as the crown of thorns cuttings will rot if the soil is too wet.
Move the crown of thorns stem cutting into bright sunlight when new growth appears, which should occur in about two weeks. At this point, water only when the top inch of the soil feels dry to the touch.