Euphorbia pulcherrima, the poinsettia, is known all over the world as the flower of Christmas. Growing naturally in Mexico, the plant was named after Joel Poinsett, who introduced them to the United States in the early 1800s.
Blooming Time: November-December. Poinsettia flowers are small golden cups, known as cyathia, at the top and center of the plant. The red, pink, or white bracts surrounding the inflorescence provide the coloring.
Culture: Euphorbia pulcherrima need a rich, well-drained soil (2 parts peat moss to 1 part potting soil to 1 part sand or perlite). During the flowering period, the plant should have protection from direct south or west sun. It should also be protected from hot or cold drafts. In the home, poinsettias prefer a night temperature of 60 to 65 degrees F and a day temperature of 65 degrees F. The soil should be kept uniformly moist, possibly requiring water 2 to 3 times a week. Fertilize every 2 weeks with a solution of houseplant fertilizer at 1 tsp per gallon. After blooming reduce the amount of water and allow the plant to go dormant. Move poinsettia to cooler position but not below 50 degrees F. In late spring, repot the poinsettia and prune it at this time to produce a more shapely plant. Usually after flowering poinsettias become leggy. Keep the plant short and compact by pinching out the tips of new shoots until the middle of August. Water the plant with a solution of fertilizer (1 tsp per gallon) every 2 weeks. Poinsettias are strongly photoperiodic. They require 12 hours of darkness each evening to bloom. Starting October 1, place a light tight box over the plant at 5:00 PM and keep it in place till 8:00 AM. Continue to water and fertilize during this period. Continue to cover the plant each evening until color begins to show in the top leaves. If these requirements have been met, color should develop in the uppermost leaves in the third week of November as the inflorescences develop.
Propagation: Euphorbia pulcherrima are propagated during the summer by allowing shoots to become 3 to 5 inches long. At this stage, remove them and pot them in sterilized sand.
Euphorbia pulcherrima was featured as Plant of the Week December 17-January 6, 2000.
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Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.