COLUMBIA, Mo. – No flower says Christmas like the poinsettia. Now is the time of year when these colorful plants adorn mantels, tables and hallways across the country.

Native to southern Mexico and Central America, the poinsettia is the most popular potted plant in the United States. Poinsettia sales are estimated to contribute hundreds of millions of dollars annually to the U.S. economy. And it happens in a very short time.

“All of the poinsettias are sold between the Wednesday before Thanksgiving and Christmas Day,” said David Trinklein, plant scientist and state horticulture specialist for University of Missouri Extension. “A poinsettia on Dec. 26 is pretty much worthless.”

Poinsettia biology

To be ready for the holiday, these plants require lengthy periods of uninterrupted darkness. In nature, long nights trigger poinsettias and other short-day plants to bloom, Trinklein said.

The colorful part of the poinsettia that we enjoy isn’t a flower. What look like petals are specialized leaves called bracts. The true flowers, called cyathia, are the small structures found in the center of the bracts.

Today’s poinsettias are not just red. You can get them in creamy white, shades of pink and orange, marbled in pink and white, and even with pink flecks on red. Many new poinsettia colors are created by mutation, not breeding. “Bract color mutates very easily,” Trinklein said. “Different colors are the result of chance mutations from the red.”

Choosing a poinsettia

When shopping for a poinsettia, make sure the leaves and bracts do not show any wilting, which could mean problems with the roots, Trinklein said. He recommends looking at the underside of the leaves to check for insect damage.

Also, take a close look at the cyathia. “It’s the presence of the true flower that indicates the plant is still relatively young,” he said. If the cyathia are missing, it’s likely the plant is past its prime.

Poinsettia care

Proper care will help the poinsettia stay beautiful throughout the holiday season. Put the plant in bright, indirect light, Trinklein said, and do not overwater.

“Poinsettias, just like most members of the Euphorbiaceae plant family, do not like wet soil,” he said. “If the plant is sitting on a saucer—I call them rug savers—be sure to empty it after the pot drains following watering.” Water left sitting in a saucer will be wicked back up into the root zone. If your plants are wrapped in decorative foil, make sure there’s a hole in the foil so water can drain.

It’s easy to determine when your poinsettia needs water, Trinklein said. Pick up the pot. If it feels light, it may need water. Then touch the surface of the soil. If the soil feels clammy or moist, it is best to wait before adding more water.

You can skip fertilizer or plant food, Trinklein said. At the time of sale, the plant’s growth period is over, so its need for nutrients is minimal.