The Aztecs used them to control fevers and make a red dye. Montezuma had them brought to what is now Mexico City by caravan because they could not grow there at the city’s high altitude.
Seventeenth-century Spanish botanist Don Juan Balme mentions them in his writings. At the same time, the Spanish Franciscan friars, who settled in the Taxco region of southern Mexico, included the timely winter-grown red blooms of the plants in the nativity procession of Fiesta de Pesebre. A three-term U.S. representative from South Carolina was appointed to be the first U.S. minister to Mexico from 1825-29. He liked the plants so much that he brought them to his greenhouse in South Carolina, and in so doing introduced the plant to the United States.
While the German botanist Wilenow gave the plant its formal botanical name — Euphorbia pulcherrima — it is known around the world by its common name, honoring that South Carolina representative and ambassador, Joel Roberts Poinsett. Yes, you knew the name of the first U.S. ambassador to Mexico all along. Today, the plant bearing his name is the best-selling potted plant in the United States and Canada.
Perhaps the greatest myth about poinsettia is that it is poisonous. Ohio State University proved that wrong in a feeding trial with lab rats published back in 1971. Researchers ground up various parts of the plant and fed them to laboratory rats. Not only did the rats not die, but it did not even blunt their appetite. By comparison, a 50-pound child could eat at least 500 poinsettia leaves and not be poisoned.
That is not likely to happen for a few reasons. First, it is tough to get kids to eat any vegetable that does not have cheese on it. Second, poinsettia leaves have an atrocious flavor, so I don’t see how one gets a child to finish even one leaf. Third, one major side effect of eating poinsettia leaves is vomiting and diarrhea. The biggest threat from a child or pet eating poinsettia is to your carpet. There is a difference between poisonous and unpalatable.
If you want to try growing your poinsettias this year and enjoy them again next year, there are several how-to guides available online. A good general paragraph on maintaining a poinsettia outdoors is in UGA’s “Care of Holiday and Gift Plants” on extension.uga.edu/publications/. An excellent, detailed, step-by-step protocol to maintain and grow your poinsettia the year around is provided in Ohio State University’s “Poinsettia Care in the Home” at ohioline.osu.edu/hyg-fact/1000/1248.html.
Poinsettia culture out-of-doors in Coastal Georgia is possible but not easy. The plants are rather demanding. This is not a plant to use for your first-time gardening experience. Maintaining the correct moisture balance in the soil is tricky around here, so yard poinsettias are a bit of a novelty.
It’s the same sort of challenge as lighting kitchen matches at 100 feet with your .22 rimfire rifle. It doesn’t happen but a couple times a year, but when it does, it’s extremely satisfying. That is why most of us are happy just to get our poinsettia to last the holiday season.  
Chlorophyll does not have to color your thumb in order to have a happy poinsettia. Rule No. 1: Bright sun. Place your poinsettia in an east-, south- or west-facing window.  Rule No. 2: Don’t let them wilt. That does not mean you should drown them. It means you should check on the soil several times a day and water as soon as the surface is dry to the touch. For example, if a 7-inch pot should be watered with two cups of water, wait five minutes and water with another two cups. Yes, this means you will be putting the plant in the sink without its foil wrapper to water it.
Once the water drains, put it back in its sleeve and back in the window. Rule No. 3: Don’t expose the plant to a draft. If the plants are put in the path of an air-conditioning vent, expect defoliation. Air temperature of 65-70 degrees Fahrenheit is best.

Gardner is the UGA extension agent for South Bryan.