The classic Christmas plant. Pictured here is a variegated poinsettia. Rich Abrahamson/Morning Sentinel

Poinsettia is a plant that usually is purchased with the idea that it will be thrown away – ideally, composted – after a few months. It makes an attractive and inexpensive holiday decoration, showing up in grocery stores and plant nurseries shortly after Halloween.

Poinsettias are native to Mexico and Central America. About 35 million of them are sold each year in the United States. They were discovered, at least in the minds of U.S. citizens, by Joel Roberts Poinsett, the first U.S. ambassador to Mexico in the 1820s. He brought them to his South Carolina home and named them after himself. Long before Poinsett, the Aztecs are thought to have used Poinsettias in war rituals, and as dye for textiles and cosmetics. The plant’s milky sap was thought to reduce fevers.

Many people believe that poinsettias are highly toxic, but that is a myth. While I’m not suggesting you eat a poinsettia, a 50-pound child would have to eat 500 leaves to have a major reaction.

Poinsettias are prized for their bracts, which are typically red but can also be white, yellow, pink, orange and various shades in between. Some are variegated, with two or more colors. The actual poinsettia flower is round, yellow and tiny, surrounded by the bracts. The botanical role of bracts is to protect the flower, which in nature produces the plant’s seed. People can plant the seeds and produce new poinsettias, but in the commercial world, most poinsettias are created from root cuttings.

When you buy a poinsettia, check the flower, called cyathia, a group of small bumps, to make sure they haven’t fallen off. If they have, the plant is nearing the end of its life cycle.

While most people throw away their poinsettias sometime before spring, you do want to keep them looking good throughout the holiday season. Poinsettias prefer indirect light at that stage of their lives, so don’t place them in a South-facing window. They like temperatures between 60 and 70 degrees Fahrenheit, which means not too close to heat vents or radiators. Also, if you go away for the weekend, don’t lower the heat too much.

They don’t like soggy soil. Water the poinsettia only if the soil is dry to the touch, and dump out any water that has drained from the hole in the pot into the saucer below it. You probably won’t have to water the plant more than once during the holiday season; just test your the soil moisture with your finger before you water.

Because they are inexpensive and it is difficult to get them to produce the colorful bracts for a second season, most people simply compost the plants after the holidays. But, if you’re up for a challenge, you can try to produce the bracts for future seasons. To do so, continue watering, but only when the soil is dry. Sometime after mid-March, move the plant to a spot with bright light and a steady 60 degree temperature; an unused room, unheated garage or near a basement window all may suffice. At this point, cut the flower’s stem to about 4 inches tall. When you see the plant beginning to grow, add liquid fertilizer every two weeks, according to the package directions.

In June, move the plant outdoors for its summer vacation in a partly shaded area. Continue watering and fertilizing. In mid-August trim the stems again, leaving three or four leaves on each one. Around Labor Day, bring the poinsettia inside to your brightest window and continue watering and fertilizing.

Around October, the poinsettia’s needs change again. It now needs at least 12 hours a day of total darkness. Put it in a closet in late afternoon, and keep the closet door firmly closed until the next morning. Then, each morning move the plant to the sunny window, water and fertilize if needed.

Around Thanksgiving, the plant goes back to the sunny window full time. Water regularly until mid-December when, if all goes well, it will put on its show for a second year.

My wife Nancy and I tried this project one winter and failed. Now, we buy small poinsettias each holiday season as soon as they appear in local greenhouses. The small price of new plants is minor compared with the cost and responsibility of keeping a poinsettia alive for a year.

Tom Atwell is a freelance writer gardening in Cape Elizabeth. He can be contacted at: tomatwell@me.com