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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Selection and Care of the Poinsettia

This article was published originally on 11/6/1998

The poinsettia is one of the most beautiful symbols of the holiday season. The bright, colorful poinsettia has become an integral part of holiday decorations in both the home and office.

History

A native of Mexico, the poinsettia has a long, fascinating history. Aztec Indians made a reddish purple dye from the poinsettia's bracts and a medicine from its milky sap.

The poinsettia was introduced to the United States in 1825 by Joel Robert Poinsett, the first U.S. ambassador to Mexico. While traveling in the country, Poinsett found the poinsettia growing on a hillside near Taxco, Mexico. He gathered and sent some plants back to his home in Greenwood, South Carolina and later distributed plants to his horticultural friends.

Initially, the poinsettia was a little known plant grown chiefly in conservatories and botanical gardens. Early poinsettias were fragile, short-lived, and tended to drop their leaves. Plant breeding programs in the last 50 years have produced dramatic improvements in the poinsettia and lead to an explosive growth in plant sales. Modern poinsettia varieties are compact, durable, hold their bracts for several weeks, and are available in a wide range of colors.

Selection

Poinsettias are available in red, pink, white, and gold. Variegated and marbled poinsettias are also available. The colorful part of the poinsettia, commonly referred to as the plant's flowers, are actually modified leaves or bracts. The true flowers are yellow to green, button-like objects located in the center of the bracts.

When selecting a poinsettia, choose a plant with dark green foliage and brightly colored bracts. The true flowers should be shedding little or no pollen. Avoid poinsettias with wilted foliage, broken stems, or few leaves. Also, check the plant for insects. Obviously, no one wants to bring an insect infested poinsettia into the home.

Care

Before venturing outside, place the poinsettia in a plant sleeve or carefully wrap it to prevent exposure to cold temperatures. Exposure to freezing temperatures, even for a brief moment, may cause the leaves to blacken and drop. As soon as you get home, unwrap the plant and place it near a sunny window or other well-lighted area. However, don't let the plant touch the cold window pane. Also, keep the poinsettia away from cold drafts or heat outlets. Poinsettias prefer temperatures between 60 and 70ûF.

Water needs can be determined by the finger test. Check the potting soil daily with your finger. When the soil becomes dry to the touch, water the plant until the water begins to flow out the bottom of the pot. If the pot is wrapped in decorative foil, punch a hole in the foil at the bottom of the pot for water drainage and place a saucer underneath the pot. Discard the excess water which drains into the saucer. Today, many florists use molded plastic pot covers rather than foil. When watering these plants, carefully remove the poinsettia from the pot covering, water the plant in the sink, then drop it back into the molded pot cover. Both over- and underwatering cause problems for poinsettias. Overwatering will cause the lower leaves to turn yellow and drop. Dry plants wilt and also drop leaves prematurely.

If given good care, poinsettias should remain attractive for several weeks, well after the Christmas and New Year's Day holidays.

Health Concern

A commonly held belief is that the poinsettia is poisonous. However, research conducted at Ohio State University and other institutions has shown that the poinsettia is not poisonous. While the poinsettia is not poisonous, it is not intended for human or animal consumption. Individuals are still advised to keep the plant out of the reach of small children and pets.

One potenital health problem associated with the poinsettia is dermatitis or an irritation to the skin. When a poinsettia stem is cut or broken, a milky sap oozes from the wound. Some individuals may develop an allergic reaction to the milky sap, resulting in a minor skin irritation.



This article originally appeared in the November 6, 1998 issue, pp. 125-126.

Year of Publication: 
1998
Issue: 
IC-479(25) -- November 6, 1998