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Charles Hesselein, James Stephenson, John Olive, J. Raymond Kessler, and Gary Keever According
to the 1997 floricultural crop survey, poinsettias represent
approximately one-third of the $701 million U.S. and $13.1 million
Alabama wholesale potted flowering plant market. Over the years
improved cultivars have greatly increased post harvest longevity,
added a variety of colors, and improved handling and growing
characteristics. These breeding improvements are one reason that
these colorful plants have become a symbol of the Christmas season
in many parts of the world.
In the summer of 1997, rooted cuttings were potted, one cutting per pot, into 6.5 inch azalea pots upon arrival at OHS (August 22 and August 26-27, 1997). All plants were planted into a pine bark:peat moss medium (3:1 by volume) amended with 6 pounds dolomitic limestone, 2 pounds gypsum, and 1.5 pounds Micromax per cubic yard. Each pot was fertilized with 0.25 ounce Osmocote 14-14-14 placed on the top of the media. Plants were fertigated weekly (starting at planting date and continuing until November 7) with 200-500 ppm nitrogen using Peter’s 20-20-20, 20-10-20, or calcium nitrate fertilizer. Additional fertilizer inputs included two fertigations of sodium molybdate (0.3 ppm sodium molybdate) on September 22 and November 3 and two fertigations of epsom salt (1,200 ppm magnesium sulfate) on October 9 and November 4. Plants were grown in glass-covered greenhouses with maximum day temperatures of 85oF and minimum night temperatures of 60oF. The terminal growth was removed from each plant (pinched) on September 8 to help stimulate branching. Five to seven nodes remained on each plant following pinching. Plants received one or two growth regulator applications to control plant height (see table). A tank combination of B-Nine (daminozide, 0.4 ounce per gallon) and Cycocel (chlomequat, 1.6 fluid ounces per gallon) was sprayed at each growth regulator application. Pest management consisted of an application of 0.5 teaspoon per pot of Marathon 1G (imidacloprid) on September 17, a drench of Truban 30 WP (etridiazole, 8 ounces per 100 gallons) and Cleary’s 3336 4F (thiophanate-methyl, 10 fluid ounces per 100 gallons) on November 3, and three applications (November 14, November 21, and December 1) of the fumigant Exotherm Termil (chlorothalonil, 3.5 ounces per 775 square feet). An application of calcium chloride (0.15 ounce per gallon) was made on November 6 and 13 to attempt to control bract edge burn. Data collected included: date of first bract color, date of anthesis (first observable pollen), number of bract clusters, diameter of largest bract cluster, plant height and diameter [(width1 + width2 )/2, where width1 is at the widest point + width2 is perpendicular to width1] (see table). On December 3 an informal quality evaluation by color group was conducted. Twenty-eight of the thirty-one cultivars were separated into six bract color classifications: red, white, pink, marble, jingle bells, and other. A representative sample of three plants was selected for each cultivar and the cultivars in each color group were ranked from best to worst by ten judges (see table). The judging team consisted of station personnel, staff from the Mobile Botanical Gardens, and a local nurseryman. RESULTS Perhaps it was no surprise that ‘Freedom Red’ and the more recent introduction ‘Freedom Bright Red’ scored at the top of our red cultivars. ‘Freedom Red’ has been the industry standard for several years. The top three white cultivars were very difficult to rank; any of which appear suitable for Gulf Coast greenhouse production‘Darylne Pink’, a top rated pink cultivar, produced a large convex bract display with unique, bright red-pink bracts. The cultivars receiving the greatest number of comments from our judges were the “other cultivars” category. ‘Monet’, ‘Candy Cane’, and ’Cortez Candy’ (Figure 1) had similar bract appearance, a whitish background with pink and red flecking, as if someone had spray painted white poinsettia flowers with red and pink spray paint. ‘Silverstar’ (Figure 2) had red bracts that covered its unusual gray-green variegated foliage. The attractive foliage of ‘Silverstar’ makes it a candidate as a flowering foliage plant in tropical and protected subtropical climates. The ‘Cortez’ (Red, Pink, White, and Candy) series produced beautiful, large plants but these cultivars required special handling, as the stems were easily broken. ‘Monet’ and ‘Candy Cane’ were also difficult to handle with stems that were easily broken off. One cultivar, ‘Dark Puebla’, had bracts that did not fully develop until after Christmas.
Consumers and growers alike are fortunate that recent poinsettia breeding is producing such a wide variety of cultivars to help brighten the Christmas holiday season. Since many of these cultivars appear to be well suited for production in Gulf Coast growing conditions, local growers have many new choices for their poinsettia “portfolio.” |
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