Poinsettias can thrive outside providing the weather conditions are warm enough. These sub-tropical flowering plants do not like the cold or frost, so put them into the ground beginning in the spring wherever winter weather is a problem.
Originally from Mexico and Central America, poinsettias thrive in the southwest region of the United States. In cooler areas such as the Midwest and Northeast, it is best to wait at least until late March to plant these popular indoor Christmas plants. Inside, make sure to keep poinsettias near good sunshine, and water them only when they get dry, before planting them in a landscape.