Poinsettia Care - December 9, 2009
Jeff Schalau, Associate Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County

Today’s poinsettia cultivars come in a wide range of colors and a variety of bract shapes and sizes. Many gardeners may know that it is the bracts and not the flowers which display the seasonal color of poinsettias. A bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower or cone scale. Ongoing poinsettia research has also produced cultivars that have stronger stems and better keeping qualities. This column will provide care tips that will extend the life of your poinsettias well beyond the holidays.

Poinsettias thrive on bright, sunny natural daylight: at least six hours daily is recommended. Placement near a sunny window is ideal, but avoid locations where hot afternoon sun may shine directly on, and fade colorful bracts. To prolong the bright red of the bracts, temperatures ideally should not exceed 70°F during the day, or fall below 65°F at night. Avoid placing poinsettias near drafts, fluctuating air currents, excess heat and dry air from appliances, fireplaces or ventilating ducts.

Poinsettias do best with a moist soil condition. Water the poinsettia thoroughly when the soil surface feels dry to a light touch. Like other container plants, the best indication of a thorough watering is water begins to seep through the drain holes at the bottom of the pot. Pour off any excess water, as poinsettias left sitting in water may suffer from root rot. It is not necessary to fertilize your poinsettias during the holiday season. However, for those that want to grow their poinsettias beyond the holidays should apply a balanced, all-purpose household plant fertilizer after the holidays to promote new growth.

Poinsettias are sensitive to cold temperatures and outside placement during the winter months is not recommended at Arizona’s higher elevations. However, an enclosed patio or entryway may be suitable if the night temperatures are mild and the delicate bracts are well protected from wind and temperatures below 55°F. Leaf drop will occur if poinsettias are exposed to temperatures below 50°F. Exposure to frost will usually kill a poinsettia plant.

Poinsettias can be grown year round for lush green foliage. In March or April, when the bracts age and turn to a muddy green, cut the stems back to about eight inches in height. After you cut the plant back, it will probably look rather stark, with bare branches and bluntly cut woody stems. By the end of May, you should see new growth. Keep the plants near a sunny window. Around July 4th, cut branches back again about half their length to encourage bushy plants. You may place your poinsettias outdoors in indirect sun when night temperatures are warmer. Continue to water the plants regularly during the growing period. Fertilize every 2 to 3 weeks throughout the spring, summer and fall months with a complete, indoor plant fertilizer.

The poinsettia is a photoperiodic plant, which means it begins to set buds and produce flowers as the winter nights become longer. The plants will naturally bloom during November or December depending upon the flowering response time of the particular cultivar. This can be tricky to do outside of a controlled greenhouse environment, because any stray artificial light could delay or halt the flowering of the plants.

Now comes the tricky part: starting October 1, the plants must be kept in complete darkness for 14 continuous hours each night. This can be done by moving the plants to a dark room, or placing a large box over them. During this period, the plants require 6 to 8 hours of bright sunlight and night temperatures between 60 and 70ºF. This regimen must continue for approximately 8 to 10 weeks in order for the plants to develop colorful bracts for the holiday season. If this seems like an exercise for people with too much time on their hands, support the horticulture industry by purchasing another poinsettia.

The above information was excerpted from Ecke Ranch’s web site at www.ecke.com. The Ecke family was important in popularizing poinsettias for use as holiday decorations and their growing operation continues to develop and supply poinsettia cuttings nationwide.

The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at cottonwoodmg@yahoo.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.

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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: December 1, 2009
Content Questions/Comments: jschalau@ag.arizona.edu
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