‘Tis the season once again, a season of indoor decorating and festivities. That ultimate Holiday houseplant, the poinsettia, is on a lot of Holiday gardeners’ minds this time of year, so this would be a good time to learn a little more about this popular Holiday hallmark.

Originating from southern Mexico, this plant was also known by the Aztecs as "Cuetlaxochitl" or Mexican Flame Leaf. Poinsettias were used in many ceremonial and herbal medicinal rituals. The sap was employed as a fever reducer, while nobles prized the rich red dyes from the color in the bracts as purity.

Once Mexico was occupied by the Europeans, the traditional uses of this plant were succeeded by the more ornamental and cultural uses, which we North Americans still practice today during the Holiday season. Aligned with its new found association with the Christian Christmas celebration, it is also is known in some areas as the Christmas Star, Noche Beuna, or Pascua.

Though highly revered for its beauty by the early European and American occupants of Mexico, credit of the name “Poinsettia” itself has been awarded to the late Col. Joel Roberts Poinsett, who was the American ambassador to Mexico from 1825 to 1829. When he returned home to Southern Carolina following his term, he brought back many cuttings of this wonderful plant which grew wild in Mexico, and presented them to the local botanical gardens to propagate. And the rest, as they say, is history.

Flower Varieties

Though the common name of this now famous plant bears Col. Poinsett’s name, the botanical nomenclature of the plant is credited to the German botanist Carl Ludwig Wilenow. The botanic name Euphorbia pulcherrima translates as “the Beautiful Euphorbia”, the genus being named after the renowned Greek physician Euphorbus, and one which includes other popular garden plants like spurge.

Plant breeders and developers have come a long way from the first common red poinsettias. Today, the list of colors includes the traditional red, along with white and pink in varying shades. As well, we now find newer colors of yellow, lime green, purple and peach, with bicolor, speckled and variegated combinations in individual varieties.

Poinsettia flowers are not actually true flowers, but rather modified bracts (special leaves) that change color during the winter season. The true flowers are the small yellow bead-like clusters found at the center of the colored bracts, which themselves are located at the terminal branches of the plant. Poinsettias can maintain these colored bracts through the entire length of winter here in our indoor climates in the North, and even into the late spring if maintained appropriately. This is dependent on a number of factors. 

Poinsettia Culture And Care

To guarantee that your poinsettia provides you with a long season of “bloom”, ensure that you maintain all cultural variables constant. Poinsettias do not like change of any kind. Light levels need to be relatively low; bright lights will cause the plant to loose color quickly, as they become convinced that the season has changed and therefore they should switch to a summer vegetative growth pattern. Moisture should always be monitored and be held relatively uniform at all times. Too much or too little water in the roots will result in the collapse of the plant.

A moderate temperature is essential for the longevity of poinsettias. Minor temperature fluctuations ranging between 60ºF (15ºC) at night to a temperature not exceeding 70ºF (21ºC) during the day is most desirable. Avoid locating the plants too near to heat registers or intake vents for furnaces, or near drafty windows, doors, or cold rooms. Sudden temperature changes in such areas can greatly affect the health and productivity of the plant.

In its indigenous environment of Mexico, the poinsettia can grow to become a large shrub or small tree, often reaching a height of 16 feet (400cm) or more. As a seasonal houseplant, it rarely achieves a height greater than 24 inches (60cm).

Poinsettias can be trained to be pot-bound and kept through the summer, and can then be forced to recolor in time for the winter holiday season. This is accomplished by keeping the plant in complete and total darkness for approximately 12 hours a day for a minimum of 6 weeks to initiate the color phase (starting approximately early to mid-September). Follow this with a move to a south window after the darkness phase. This will trigger the growth phase and the new leaves will emerge colored. Any light entering the plant during the 12 hours of the dark phase will reduce the depth of the resultant color. And be sure that the plant does not dry out during this period.

A Common Yet Erroneous Myth

Finally, there is a persistent and strongly-held belief that poinsettias are poisonous. While it is true that there are some individuals that may be allergic to the latex produced in the sap of the poinsettia, there is no evidence showing that this Holiday favorite is poisonous, nor is it toxic. They are, however, definitely not edible. Poinsettias can therefore be harmful to small pets and children who may eat the petals. It would be wise to display them with caution and out of reach of the curious.

And thus concludes the story of the poinsettia. Until next time, Happy Holidays and Happy Gardening!

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