One of the most popular plants that we see this time of year is the Poinsettia. Many are sent as gifts to family members or to businesses with the idea that they will sit out for 1-2 months and then be tossed into the garbage with all the other disposable decorations. The truth is that you can keep a poinsettia alive all year and use it again for the next winter season.
The plant that we call Poinsettia was first brought to the United States by Joel Robert Poinsett (founder of the Smithsonian Institute) during his ambassadorship to Mexico between 1825 and 1829. It was assigned the botanical name Euphorbia pulcherrima Willd ex Klotzsch meaning "very beautiful".
By 1923 the Poinsettia was cultivated for use in landscaping and the fresh cut flower industry as a specialty of Albert Ecke, a German emigrant, who grew the shrubs near Los Angeles in Encinitas California.
If you want to keep the poinsettia alive after winter then it is best to start with healthy plants that are disease and insect free. Not only will it help if your plant is full of vigor but you do not want to harbor insects and disease that might spread to your other house plants.
While maintaining Poinsettia during the winter, keep the plant near indirect, natural daylight for six hours each day. Avoid placing the plants near drafts, excess heat, or the dry air from appliances, fireplaces, or ventilating ducts. Do not exceed day time temperatures of 70 degrees F or night time temperatures of 50 degrees F. Fertilizer is not necessary while the plant is in bloom.
Water Poinsettia as you would any house plant by providing deep water when soil is dry. Do not leave the plant in the decorative sleeve that usually surrounds the pot. This sleeve does not have holes and will not allow water to drain from the pot. Standing water will choke your roots or cause root rot and kill your poinsettia.
After the winter season, the colorful bracts will lose their aesthetic appeal. When this occurs, sometime around March or April, cut your plant back to about 8 inches in height. When night temperatures outdoor are 55 degrees F or higher, you can move any Poinsettia outdoors. Here it will be able to absorb the warmth of spring and summer. By the end of May you should see vigorous new growth from the late winter cutting. During this time continue regular watering, fertilizing every 2 to 3 weeks throughout the spring, summer, and fall months with a well-balanced, complete fertilizer. Transplanting can be done around June 1 if it is necessary. Pruning may be required during the summer to keep plants bushy and compact. Do not prune after September 1.
New buds will set as the nights lengthen during fall. This is due to the photoperiodic nature of Poinsettia and allows them to bloom naturally around November or December. However, any stray light, such as outside street lights or household lamps, will delay or halt the re-flowering process. The plants must be kept in complete darkness for 14 continuous hours each night starting October 1 or 2 months before you would like the plant to flower. Accomplish this by moving the plants to a totally dark room, or by covering them with a large box overnight. During October, November, and early December, the plants require 6 to 8 hours of bright sunlight daily, with nighttime temperatures between 60 and 70 degrees F. Temperatures outside this range may delay flowering. Continue the normal watering and fertilizer program. Following this regime for 8 to 10 weeks should result in a colorful display of blooms for the holiday season.
The biggest problem of concern with Poinsettia may include whitefly, mealybugs, red spider mites and scale. Root or stem rots can also occur if the plants are overwatered.
Contrary to popular belief, poinsettias are not poisonous. Studies conducted by Ohio State University in cooperation with the Society of American Florists concluded toxicity was not evident at experimental ingestion levels far exceeding those likely to occur in a home environment. According to POISINDEX Information Service, a 50-pound child who ingests over 500 poinsettia bracts would not demonstrate levels of toxicity. However, it is not recommended that you allow children to eat poinsettia as they may develop stomach cramps or other side effects.
Helpful Publication: Poinsettia: Plant of the Month. Horticulture Update. November/December 2000. Texas Agricultural Extension Service. College Station, Texas; Benson, D. Micheal. The History and Diseases of Poinsettia, the Christmas Flower. Plant Health Progress. February 12, 2002.
The Extension office is located in Kennett, Missouri at 101 South Main Street (the old bank) on the 2nd floor. Open Monday -- Friday or you can call 573-888-4722 if you have a question. University of Missouri Extension programs are open to all.
Sarah Denkler is a horticulture specialist
with University of Missouri Extension
in Dunklin County.