The poinsettia is a popular Christmas plant, but it's also an annual plant that requires specific care to keep it thriving. After Christmas, you can either keep it as a houseplant or plant it outside. If you choose to keep it indoors, place it in a sunny location and water it only when the soil is dry. If you decide to plant it outside, choose a spot with well-drained soil and partial shade. Fertilize it every month with a balanced fertilizer and water it regularly.