Postharvest flower life was the same regardless of the relative humidity the plants were exposed to (70-93%) during production. However, plants grown under high relative humidity (90-95%) produced more dry weight than when grown under lower humidity (55-60%). As with most if not all potted plant species, should be grown in dark colored pots as light colored ones allow light to reach the root ball and can negatively impact plant growth and performance. Leaching of subirrigated grown plants at harvest should be done using water having a total volume of twice the pot volume of mix. Under Southern California conditions, full light grown plants exhibited more leaf fall and yellowing compared to ones grown under 50% light reduction and the resulting average 3-4 degree F lower temperatures. Preharvest sprays of calcium can reduce both Botrytis and bract necrosis (edge burn). Treating unrooted cuttings with MCP just prior to shipping seemingly offers little if any benefit. Providing plants lower light levels starting 3 weeks before harvest can reduce postharvest leaf and cyathia drop.
Member of the Euphorbiaceae (spurge family).
Native to Mexico.
Relatives include croton, rubber tree and castor-oil plant.
Showy red, white, pink, cream or bicolored “flowers” are actually bracts, which are modified leaves below the actual flowers (cyathia).
Actual flowers are small, mostly yellow with some red, clustered together along with glands and is called a cyathium (plural, cyathia).
Plant is classed as a dicotyledon, leaves not parallel veined.
Flowers are not fragrant.
Somewhat chill sensitive, store at 50-55 degrees F.
The specific epithet name “pulcherrima” means very handsome. Named after Euphorbus, the physician to the king of Mauritania, Juba. In addition to the many ornamental species in this family, others yield rubber, edible fruits and roots and have valuable medicinal properties.
Before Christianity came to the Western Hemisphere, poinsettias were believed to be a symbol of purity by Indians near present-day Taxco, Mexico, where this species originated. Called Cuetlaxochitl, it was also used to make a reddish dye and the latex was used to counteract fever. In the 1600’s, Franciscan priests settling near Taxco began to use this plant in festivities that occurred at the time it flowered in December. Some 200 years later in 1825, Joel Robert Poinsett introduced this plant to the US while serving as US Ambassador to Mexico.
Modern day poinsettia production began in southern California in about 1909 when the Ecke family grew them as cut flowers. In 1923 Mrs. Enteman of Jersey City, NJ noted a seedling with unusual characteristics that eventually became the genetic model for most cultivars grown as potted plants until the early 1960’s. It was named ‘Oak Leaf’. Until this time, premature leaf and bract (flower) fall were major problems. In 1963 the Mikkelsen family of Ohio introduced the first long-lasting cultivar, ‘Paul Mikkelsen’.
Will generally do well in light levels at least bright enough to read a newspaper in comfort but more light would be better. Some favorite cultivars and their respective flower colors include ‘Freedom Red’, ‘Winter Red’ (unique flower form), ‘Freedom White’, ‘Freedom Pink’, ‘Peterstar’ (marble) and ‘Marblestar’. In volume, it is the number one potted flowering plant grown in the US. It requires long nights (short days) to initiate flowering. To re-flower plants held over from the previous year, place them in total darkness for 12 plus hours per day and flowering should take place within 9-10 weeks, depending on cultivar and growing conditions.
Because of its popularity and its association with Christmas, many mass market outlets begin selling this plant before Thanksgiving as a way to get consumers in the Christmas buying spirit. As a result, many poinsettia plants are mistreated and unfortunately look rather ragged in many of these stores. While many other Euphorbia species have been shown to cause dermatitis related problems with some individuals, this one is not toxic if ingested.
Recent Research Findings:
Ter Hell and Hendriks (1995) noted that high levels of ammonium fertilization during production caused increased abscisic acid and decreased cytokinin levels resulting in increased leaf drop and root damage after harvest. Using ‘Red Velvet’, King et al. (2001) noted a delay in leaf yellowing when the experimental growth regulator TDZ was applied. Others using different cultivars could not always confirm this finding.
Under retail and consumer conditions and whenever possible, lower or fold back any pot coverings such that more light can reach the lower leaves.