The poinsettia (Euphorbia pulcherrima) has become the most popular container-grown plant for the Christmas season. A native of Mexico, the plant was discovered in 1825 by Joel Robert Poinsett, the first U.S ambassador to Mexico. The plant is named for him.

In tropical climates, the poinsettia grows as a perennial and may become a small tree. It is primarily a houseplant in West Virginia, but it may be grown in the Garden during the summer.
The colorful part of the poinsettia is not the flowers, as is commonly thought, but the colored leaf-like bracts. The actual flowers, located in the center of the colored bracts, are relatively inconspicuous. The bright red bract varieties remain the most popular.

Newer colors range from mixed white and pink, mixed pink and red, and mixed red and white to solid pink. Poinsettias may be kept from year to year, but they do require some basic care and maintenance to cause them to produce the brightly colored bracts.

Many homeowners consider the process too challenging and treat the plants as “period” plants. They enjoy the plants for the period for which they are intended and then discard them.
Unfortunately, the myth regarding the toxicity of the poinsettia continues. Many folks still refuse to allow a poinsettia plant in the house because they’re afraid it’s toxic. No other consumer plant has been as widely tested for toxicity as the poinsettia, and the plant has been declared nontoxic.

Research at Ohio State University has shown that no part of the plant is poisonous and that a 50-pound child would have to eat 500 to 600 leaves and bracts to exceed the experimental doses that found no toxicity. This is not to say that the poinsettia should be a
part of your holiday menu this year. Ingestion may cause stomach discomfort and vomiting in some individuals.

You may safely use beautiful poinsettia plants to add brilliant color to the festive holiday season.
There are several steps you can take to keep the plant “in color” as long as possible. Poinsettias do best when placed in a bright location (east, southeast, or west window). Avoid the intense sun of a south window and any sudden temperature changes caused by drafts and heat vents. Night temperatures should stay above 60 degrees and day temperatures above 72 degrees.
Keep the soil in the container moist at all times but not wet. Stress caused by overwatering or extreme drying may result in leaves turning yellow and dropping.

Three weeks after you get the plant, apply a complete houseplant fertilizer with relatively low nitrogen content. Repeat this application every three weeks until the colored
bracts drop. Apply the fertilizer at the rate recommended on the fertilizer label.
In several weeks, the poinsettia will begin to lose its colored bracts. (Some plants may hold their bracts for many weeks, depending on the care the plant has received.)

When the bracts fall, the plant is going into its rest period. Gradually reduce the frequency of watering without allowing the plant to dry out. Move the plant into a cool location (45 to 55 degrees). The plant should receive some light (northeast or east window).

Maintain the plant in this manner until spring. Repot the plant in the spring using a good-quality
potting soil; cut the stems back to 3 to 6 inches. Gradually move the plant into bright light as new foliage develops. Pinch the new growth to keep the developing plant compact. Development of flowers and colored bracts is controlled by the quality and number of light hours the plant receives.
Poinsettias will not bloom if they receive constant light during flower bud formation. A healthy plant should produce colored bracts. Beginning in early October, expose the plant to the short-day treatment. Place the plant in a dark room at 5 p.m. and bring it back into bright light at 8 a.m. Continue this treatment until the bracts begin to show color. The plant should be in full bloom by mid-December.

Richard Zimmerman, Horticulture Specialist, WVU Extension Service