Caring for a Crown of Thorn Cactus

Location

• Crown of thorns is native to Madagascar and thrives in warm weather. The plant may be cultivated outdoors in USDA Plant Hardiness zones 8 through 11, or indoors where it receives bright light. The plant works well in a rock or container garden in full sunlight, and may be used as a low-growing, protective hedge. Crown of thorns is tolerant of salt and may be grown in coastal gardens.

Culture

• Like most succulents, crown of thorns requires a well draining, infertile soil that is sandy and light. The plant is quite drought tolerant, though occasional watering will help the plant to keep its leaves and flower regularly. Apply a diluted, slow release general purpose fertilizer in mid-spring and mid-fall to encourage healthy growth. Reduce watering and withhold fertilizing during the winter to allow the plant to withstand winter dormancy.

Propagation

• Crown of thorns may be propagated by taking tip cuttings in the spring or early summer. Cut off a 3- or 4-inch cutting and allow it to dry for about a day. Spray the cut on the original plant with water to keep the plant from bleeding excessively. Place cuttings in a slightly moist mixture of peat moss and sand and set it in a location with bright light. Rooting will occur in six to eight weeks.

Considerations

• All parts of crown of thorns are poisonous if ingested. Use caution when handling a bruised or broken plant, as the milky sap that the plant releases can irritate those with sensitive skin. According to the University of Florida, the sap contains diterpene esters and other tumor promoting chemicals. The exceptionally sharp spines of the plant can be a danger to children and pets. Overwatering or overfertilizing may prevent the plant from flowering and lead to rot and other complications.