These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.
Keeping Poinsettias Healthy
December 7, 2000
Poinsettias are a featured live decoration for the holiday season. Cared for properly, they are quite attractive. Improperly cared poinsettias look poor quickly. To help keep your poinsettia healthy for the holidays, follow a few basic guidelines.
One of the major enemies of poinsettias located in homes or offices is fluctuating temperatures. Keep the plant out of warm drafts, such as from heat ducts or radiators. Likewise, don't put the poinsettia near an entrance where it will constantly get a cold draft. An optimum temperature range would be 60 to 68; temperatures above 75 can cause decline. Another related problem is excessively dry air.
A second major problem commonly affecting poinsettias displayed indoors is "drowning" of the roots. Roots of poinsettias, along with all other plants, need to have air. Don't overwater poinsettias; wait until the soil surface begins to dry slightly before watering. Don't let it completely dry out and become hard, however.
Oftentimes poinsettias come wrapped with foil around their pots. Either remove this wrap or place some holes in it so water can escape. This will avoid having the plant stand in water.
The showy "flowers" of the poinsettia are actually modified leaves called bracts. The true flowers are actually found inside the colored bracts and are yellow in color. For a poinsettia to develop the colored bracts, the plant needs to have long nights.
The critical daylength is actually 12-1/4 hours. If the daylength is longer, only vegetative growth will occur. If daylength is shorter than 12-1/4 hours, then the plant will begin to develop flower buds and colored bracts.
For many years, the poinsettia was considered to be poisonous. Extensive tests have proven this to be false. However, as with most plants, a child or pet could still have stomach distress if they were to eat poinsettias.
Poinsettias were cultivated by the Aztecs in Mexico, and are believed to be native to present day Taxco. Joel Robert Poinsett, United States Ambassador to Mexico, found the plant on hillsides of Taxco in 1825. He was the first to bring the plant to the United States that same year. Extensive cultivation and breeding starting in the early 1900's has led to the wide variety of poinsettias available today. In addition to the ever-popular red, poinsettias are also available in white, pink, and variegated pink and white varieties.
For more information on poinsettias, please visit our Poinsettia Pages website.