Where did they come from? What makes them popular? And, most important, how can you keep them looking great? by Michelle Gervais issue Photo/Illustration: Steven Cominsky Poinsettias are a part of the holiday season that everyone takes for granted, like Christmas trees, white lights, and fruit cake. But where did they come from? What makes them popular? And, most important, how can you keep them looking great?Poinsettias (Euphorbia pulcherrima cvs.) are native to Mexico, where the Aztecs used them in the 14th, 15th, and 16th centuries both for medicinal purposes and for making dye. They were introduced to the United States in 1825 by Joel Robert Poinsett, the first United States ambassador to Mexico. In addition to politics, Poinsett had a passion for botany and would wander the countryside looking for new and interesting species. He is also responsible for introducing the American Elm to Mexico, as well as for establishing the Smithsonian Institution in Washington, D.C.Nowadays, the poinsettia is the best-selling potted plant in the United States, and the vast majority comes from one source, the Paul Ecke Ranch in Encinitas, California. The popularity of the poinsettia as a holiday decorating staple is due completely to the members of the Ecke family, who have worked tirelessly for decades to market the plant.Contrary to popular belief, poinsettias are not poisonous if ingested. Apparently, the rumor started due to a story about an army officer's child who ingested a leaf in 1919 and died soon after. Poinsettia producers have been fighting the myth ever since. Researchers at Ohio State University have done extensive tests with rats, with no adverse effects. The American Medical Association has also stated that poinsettias are not poisonous. Poinsettias are a part of the Euphorbia family, members of which exude a milky sap when broken open. While not poisonous if injested, the sight of the sap can be alarming, and probably contributes to the myth. In many species, this sap can cause mild skin rashes.Success with poinsettias begins with selection. Look for a plant with dark-green foliage, completely colored bracts, and no sign of wilting or yellowing. If it's cold outside, make sure the salesperson you buy the plant from wraps it properly before you take it outside to your car. Exposure to cold temperature for even a few minutes can prove deadly. When you get your poinsettia home, unwrap it and place it in a cool, sunny location away from drafts. Water whenever the soil feels dry, but never let the pot sit in water. Always pour off excess water from its saucer.For more information on poinsettias, including tips for making your poinsettia bloom again next year, check out the University of Illinois Cooperative Extension's Poinsettia Pages at http://www.urbanext.uiuc.edu/poinsettia/and The Paul Ecke Ranch homepage at http://www.ecke.com. View the discussion thread.