Originally from Madagascar, the crown of thorns is a succulent plant with multiple woody stems covered in stout thorn-like spines, and growing this plant may seem intimidating. Also known as the Christ Plant or Siamese lucky plant, the crown of thorns has dark green, tear shaped leaves that don't live for long. Most of the leaves are found at the top of stems. The plant can grow to be about 3 feet tall with proper care. Inch-wide blooms in shades of red, yellow, or pink appear at the ends of the stems, on top of the leaves. Although it doesn't look like one, it is a succulent, so water management is important to its development and growth. Over watering can kill this plant.
All parts of crown of thorn are extremely poisonous so keep it away from children or pets if they are prone to chewing on or eating plants. The sap is a skin irritant, and poisonous if ingested, so wear gloves when handling the plant and wash thoroughly afterwards.
Crown of thorns is hardy in USDA zones 9 through 11. It prefers full sun but will grow in partial shade. Space plants 18 to 24 inches apart in sandy soil. In other zones, this plant should be grown as a houseplant where it will bloom during the winter.
Crown of thorns requires bright sunlight for the best blooming. With enough light, it can bloom all summer long and into the fall and winter. Under ideal circumstances, it will bloom all year with repeated waves of blooms. At the very least, make sure it gets at least one hour of bright sunlight per day. If keeping it inside, put it in a sunny window. Water your crown of thorns once a week while blooming. Make sure it dries out completely before watering again.
While the crown of thorns plant is blooming, feed it regularly with half-strength balanced fertilizer. Discontinue fertilization after blooming ends. This is also the time to cut back on watering and let the plant dry out completely before watering. While dormant, it should be watered only once a month. If the leaves start to turn yellow and drop off, or if the stems become spongy, suspect that it is due to over watering. Quit watering all together and see if it recovers.
When the plant goes dormant, following a blooming cycle, you can shape it by pruning the stems wherever you want the plant to branch. To prevent it from bleeding the milky sap, spray it with the hose to wash the sap away. You can take the trimmed off pieces, let the sap dry and the cut callous over for a day or so, then plant the cutting in sandy soil. Keep the soil barely moist until the plant roots. Try to avoid over watering or it will rot.