Crown of thorns (poisonous to pets and the sap causes skin irritation) set in window with direct sun hours. Water at dry or dry in winter. Fertilize every monthly in winter. Remove all soil to replant every other year.
Crown of Thorns Crown of thorns has long been a favorite houseplant because it bears abundant flowers without much attention. It will be happiest in a bright spot with indirect sunlight. Keep roots moist (but not wet) and let the surface soil dry out before watering again. With enough light, the 3-foot stems can bear tiny red flowers almost all year long.