Poinsettia is perhaps the most common plant gift of the Christmas season. It is colorful, traditional and looks like it should be tough to withstand any conditions in the home. Many recipients assume that it will last for months in the home environment. Cared-for properly and the poinsettia will give weeks of color and pleasure to its owner.
But, it can be challenging to grow poinsettias in the home under normal house conditions. Many homes are kept too hot, causing the air to dry out and leaves to drop. Occasionally the plant was fertilized in the greenhouse only minimally. Or the plant may have gotten a draft in the store where it was sold. If the plant already had leaves with a yellowish cast to them when you received it, then they will not last long into the winter. Often the red, white or pink bracts (often thought of as the flower itself) will stay on the plant longer than the green leaves.
Perhaps the most important thing you need to care about is proper watering. Read more here