The poinsettia is the traditional Christmas flower. It was introduced to the United States in 1825 by Joel Robert Poinsett, first U. S. ambassador to Mexico who obtained plants from the wilds of southern Mexico.
The colorful parts of the poinsettia are actually modified leaves called bracts. The real poinsettia flower is the small yellow "ball" in the middle of the colored bracts. The real flowers are petal-less and often fall off indoors due to low humidity and light levels. Poinsettias are available in many colors in addition to the traditional red, including pink, white, and many multi-colored varieties. Blue and purple plants are died and not true flower colors.
When purchasing a poinsettia, look for two main features: healthy foliage and tight, intact "real" flowers. Avoid plants with yellow or damaged leaves because this could indicate poor handling, old plants, or a root disease problem. Tight "real" flowers indicate the plant is in an early stage and will last a long time. Once you choose the right plant, be sure it is well wrapped when you take it outside for your trip home. Even short exposure to low temperatures can injure leaves and bracts.
Once home, unwrap the plant as soon as possible. The best location for it is near a sunny window or another well-lighted area. A window that faces south, east or west is better than one facing north. Do not let any part of the plant touch the cold windowpane because this may injure it.
Proper watering is important. Examine the soil daily, and when the surface is dry to the touch, water the soil until it runs freely out the drainage hole in the container. Discard the water that collects in the outer foil wrap or saucer. Do not leave the plant standing in water. Overly wet soil lacks sufficient air, which results in root injury.
Poinsettias prefer temperatures between 60-70 degrees Fahrenheit. They do not tolerate warm or cold drafts so keep them away from radiators, air registers, and fans as well as open
windows and doors. To extend the blooming time further, place your poinsettia in a cooler location at night.
Finally, please be sure to note and tell your friends that poinsettias are not poisonous. Extensive laboratory testing and university research have concluded that poinsettias are not poisonous. However, this does not imply that they are edible. Also, some people develop a dermal reaction (skin rash) if exposed to the white, milky sap of poinsettias.
To learn more about caring for poinsettias, check out my ILRiverHort YouTube video at go.illinois.edu/ILRiverHortvideos.