Very few plants are as closely associated with a holiday as poinsettias are with Christmas. The poinsettia, native to South America, was given the botanical name Euphorbia pulcherrima, which literally means "very beautiful." Its popular name honors Joel Roberts Poinsett, the first U.S. ambassador to Mexico, who introduced the plant here.
Poinsettias make great holiday decorations and they’re often given as gifts in late November and throughout December. The showy portions of the poinsettia, which most people think of as the flower, are actually colorful leaves called bracts. In addition to the traditional red, bracts can be pink, white, orange, and even purple. Poinsettia plants come in many sizes and their bracts come in a wide range of shapes.
Until about ten years ago, poinsettia bracts dropped off the plant if it was kept indoors for more than a few days. Intensive breeding programs have produced new varieties—or cultivars—that retain their foliage and bracts indoors.
Some new cultivars involve unusual color combinations or blooming time. The bracts of the Ice Punch cultivar come out red and turn white as they grow. The color pattern of Peppermint Twist's bracts varies from one plant to another, giving each plant a unique look. Advent Red—an annual that blooms as early as October—has been cultivated primarily as a landscape plant.
With proper care, your poinsettias may stay colorful for many months. Poinsettias can retain their color until March if they are not exposed to freezing temperatures.
Keep your poinsettias away from drafts and chilly air. Poinsettias grow best in well-lit areas, but direct sun or hot lights can dry out the plants. Water your poinsettia when the surface of the soil is dry to the touch. Place a saucer under the pot, and drain the saucer if water starts to collect in it. Keep the soil from getting soggy. Too much water can kill a poinsettia. Slightly humid air will help prolong the plants' color and life span; consider misting the plants with a sprayer or placing them on gravel trays.
Do not fertilize your indoor poinsettias until you are ready to move them outside. High levels of fertilizer will reduce the quality of the plant.
When the holidays are over, consider saving your poinsettia to plant in the landscape. After the last frost, prune your poinsettia by removing the faded red bracts. Pick a spot where it'll receive full sun for most of the day. Poinsettias grow best in moist, well-drained, fertile soils.
You'll need to pinch back your poinsettia several times during the summer. This helps create a full plant with lots of flower heads. Remember that poinsettias are tropical plants and must be protected from frosts and freezing weather. Also, make sure to keep your poinsettia away from artificial light sources at night during the fall, as this can delay or completely prevent flowering.
Contrary to popular belief, poinsettias are not poisonous, although some people are sensitive to the sap, which contains latex.
For more information on zinnias, contact your county Extension office.