Originating from Madagascar, the crown of thorns plant is a low-maintenance plant that can be container-grown or planted outdoors in warmer climates. This plant grows sharp spikes over its stems, and blooms during the warm growing season in small but vibrant flowers that are white, yellow, pink or red. The crown of thorns plant can bloom year round in tropical climates or when it's grown indoors.
Water your crown of thorns plant moderately once or twice each week during the growing season. Allow the soil to dry out between waterings.
Place your crown of thorns plant in full, bright sunlight. Maintain warm air temperatures around the plant of at least 60 degrees Fahrenheit.
Treat your crown of thorns plant for mealybug or aphid infestations by spraying and wiping down the leaves with a mixture of 2 tablespoons liquid dish soap and 1 quart of water.
Trim back your crown of thorns plant in the winter, if you're controlling its size and keeping it in a shrub form. Do your pruning only during the winter, when the poisonous sap will flow the least.