   Poinsettia History and Culture - December 13, 2017 Jeff Schalau, Agent, Agriculture & Natural Resources University of Arizona Cooperative Extension, Yavapai County Poinsettias are everywhere during the holidays and many people like to continue to grow them as an indoor plant during the rest of the year. They are easy to grow, but to produce the characteristic color, you will need to have the knowledge and facilities. Poinsettias are also big business. Poinsettias are the highest selling potted plant in the U.S. Each year, Americans spend $144 million (2013 USDA Floriculture Statistics) on poinsettias and they are commercially grown in all 50 states (California has the highest production). Poinsettias are native to Mexico and the Aztecs called poinsettias "Cuetlaxochitle." During the 14th - 16th century the sap was used to control fevers and the bracts (modified leaves) were used to make a reddish dye. Montezuma, the last of the Aztec kings, would have poinsettias brought into what now is Mexico City by caravans. Poinsettias could not be grown there because of the cooler temperatures. Joel Roberts Poinsett was the first United States Ambassador to Mexico being appointed by President Andrew Jackson in the 1820's. He took cuttings from the plant and brought them back to his greenhouse in South Carolina. While Poinsett had an outstanding career as a United States Congressman and Mexican Ambassador, he is best remembered for introducing the poinsettia into the United States. Poinsettias are in the Euphorbiaceae family. Many plants in this family ooze a milky sap. In mild climates, poinsettias can be planted in the soil and grown into large perennial shrubs. The showy colored parts of poinsettias that most people think are flowers are actually colored bracts (modified leaves). The true flowers (or cyathia) of the poinsettia are found in the center of the colorful bracts. When selecting poinsettias, look for plants with dark green foliage down to the soil line and bracts that are completely colored. Avoid plants that have green around the bract edges and/or fallen or yellow leaves. The plant should be balanced and attractive from all sides. Check the true flowers which are located at the base of the colored bracts. If the flowers are green or red-tipped and fresh looking, the bloom will hold its color longer than if yellow pollen is covering the flowers. When you take the poinsettia home, be sure to have it sleeved or covered when outdoor temperatures are below 50 degrees F. Once you get the plant home, place it near a sunny window. Keep it away from warm or cold drafts and do not allow the plant to contact cold windows. Ideally poinsettias require daytime temperatures of 60 to 70°F and night time temperatures around 55°F. High temperatures will shorten the plant’s life. Move the plant to a cooler room at night, if possible. Check the soil daily. Be sure to punch holes in foil so water can drain into a saucer. Water when soil is dry. Allow water to drain into the saucer and discard excess water. Fertilize the poinsettia if you keep it past the holiday season. Apply a houseplant fertilizer once a month. Cut the stems back to 4 to 6 inches in February to promote new growth. In May, repot it to a larger container. Once nightly temperatures stay above 60 degrees F, you can move it outside. Turn the plant to keep it full and minimize root growth outside the pot. Bring it indoors before nighttime temperatures dip below 55 degrees F. You should also stop fertilizing it at this time. Coloring of the bracts and flowering is induced by shortening the photoperiod (day length). From late September to December 1, the plant should be kept in total darkness between 5 PM and 8 AM. The plant should initiate flowering and start to show some color. After December 1, your poinsettia can be left out and enjoyed through the holidays. If this sounds like too much work, then support the green industry by purchasing new plants each year! Look for additional poinsettia information with the online edition (see URL below). Follow the Backyard Gardener on Twitter – use the link on the BYG website. If you have other gardening questions, call the Master Gardener help line in the Camp Verde office at 928-554-8992 or e-mail us at verdevalleymg@gmail.com and be sure to include your name, address and phone number. Find past Backyard Gardener columns or provide feedback at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/. Photos 
Poinsettias (Euphorbia pulcherrima) showing their characteristic holiday bloom (Scott Bauer, USDA Agricultural Research Service, Bugwood.org).Additional Resources Fun Facts About Poinsettias University of Vermont Extension pss.uvm.edu/ppp/articles/points.htm  |