Crown of Thorns is a deciduous, herbaceous, perennial shrub with bright green leaves and greenish flowers. The flowers are enclosed within long-lasting and bright bracts of red or yellow. The plant is loose in form, spiny and irregularly shaped, with thick, black spines and its historic presence in the Middle East led to the belief by some that the stems of this plant had been used in Christ’s crown of thorns, hence the common name. In its country of origin (Madagascar) the plant will grow to 5 or 6 feet tall; however, in the United States, it typically grows to 3 feet, or 2 feet when grown as a houseplant.

Crown of Thorns grows best in dry to medium moisture, well-drained soils in full sun. Because it does not like wet, cold soils or temperatures below 35 degrees F. It is an easy to grow indoor plant where it prefers a sunny location in soil-based potting mix. If grown outside in hot summer climates, provide the plant with midday shade and moderate moisture for better flower bloom. You can propagate the plant from tip cuttings; however, because the resulting white latex sap causes a mild poisonous reaction when in contact with skin or eyes, wear gloves when working with this plant.

Sticky, showy, paired-bract flowers on gray stems with long spines identify this plant. Cyclical leaf drop is normal, but messy and preceeds the plant’s resting season (usually winter).  The flowers will bloom throughout the year. The long spines are dangerous to inattentive gardeners, children and pets. The plant is often used as a specimen plant for interiors with high light or as annual outdoor plant.

Crown of Thorns prefers bright light, dry soil and low relative humidity. You can propagate the plant from cuttings, but let sap dry before placing the cutting in a growing medium. Be sure to wear gloves to prevent skin and eye irritation.

Diseases, Insects, and Other Plant Problems: No known serious pests or diseases. As with most indoor plants, potential disease pests include leaf spots, stem and root rots and botrytis blight. Potential insect pests include scale, mealybug, thrips. and mites.