Crown-of-thorns, or Christ plant, is a spiny shrub from Madagascar that can bloom nearly all year. It is a popular houseplant across the U.S. and a landscape shrub in the warmest, nearly frost-free parts of the country. The bright red, pink, yellow, or white 'petals' are actually surrounding tiny flowers.
Appearance
- Growth form
- A dense, many-stemmed shrub with gray, angular, zigzag stems covered in sharp spines. It reaches 5–6 ft (1.5–1.8 m) in Madagascar but usually about 3 ft (0.9 m) in U.S. gardens and under 2 ft (60 cm) as a houseplant.
- Leaves
- Smooth, bright green leaves 1–3 in (2.5–7.5 cm) long grow only on new growth. Dropping leaves before a winter rest is normal.
- Flowers
- Tiny green flowers sit inside pairs of long-lasting, petal-like bracts about 1/3 in (1 cm) across, in red, pink, white, salmon, or yellow.
- Flowering time
- Outdoors in warm southern climates it blooms mainly in winter and spring; as a houseplant, from late winter into fall.
Where it lives
- Typical habitats
- Houseplants
- Gardens in frost-free areas
- Greenhouses
- Range
- Native to Madagascar. In the U.S. it is grown as a houseplant nationwide and outdoors in USDA zones 9a–11b.
- Preferred conditions
- Full sun (at least 6 hours) and dry to moderately moist, well-drained, sandy or rocky soil. It suffers in cold, wet soil and below about 35°F (2°C).
Growing it
- Care
- Easy to root from stem cuttings—let the sap dry before planting. Deer and rabbits leave it alone, and in warm climates it makes a low hedge or barrier.
- Toxicity
- The milky sap () in all parts can cause skin rashes and serious eye injury, and chewing it blisters the lips and mouth. Keep it away from children, dogs, cats, and horses, and wear gloves when handling.
Name and classification
- About the name
- The species name honors Baron Milius, a governor of Réunion who brought the plant to France in 1821. The commonly grown form is often treated as var. splendens.
- Varieties and forms
- Many hybrids and cultivars vary in bract color and size, and some have green-and-white leaves. Thai hybrids have much thicker stems.
Conservation
- IUCN Red List
- LCLeast ConcernLow risk of extinction
- Status
- International trade in wild plants is regulated under CITES Appendix II, like other succulent spurges.
Culture and stories
- Culture and stories
- The name crown-of-thorns likely comes from a legend that the crown placed on Jesus's head was made from this plant.
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