Text by Anne Skinner, UCCE Master Gardener

 

Poinsettias, the classic holiday flower, are popping up in stores and nurseries. Here’s what you need to know to get the healthiest plant to last the holiday season.

Poinsettias are a tropical plant, native to southern Mexico and Central America. They were discovered by Dr. Joel Robert Poinsett, a botanist and the first United States ambassador to Mexico. Poinsettia, in honor of Poinsett’s discovery, was designated as the plant’s popular name by Col. Robert Carr, a gardening friend.

The exotic plant naturally turns red at a time of year when most flowering plants are dormant. The red color on the plant is actually a large bract, which are modified leaves. In 1833, the plant was formally named Euphorbia pulcherrima (meaning most beautiful euphorbia).

Euphorbias have a structure unique to the genus called a cyathium, which consists of fused bracts that form a cup around the very small true flowers. In the poinsettia, these are the yellow areas at the center of the groups of bracts. Euphorbias also have milky white sap containing latex, so wearing gloves when grooming the plant is advisable. If using the plant as a cut flower, dip the stems in boiling water for a few seconds to prevent sap bleed. All parts of the plant are mildly toxic, so it is wise to keep them away from children and pets.

Poinsettias are naturally a leggy shrub and thus were sold as cut flowers. Plant breeding by Paul Ecke Ranch in Encinitas, Calif., developed a hardier, compact, more vigorous plant and they became a holiday sensation as a potted plant.

Poinsettias are available in early blooming and later blooming varieties. They can be found in stores before Thanksgiving, but an early variety may not last the whole holiday season. After the flowers shed their pollen, the plant drops its bracts and leaves. For longer plant life, choose plants with little or no yellow pollen showing, when the cyathia are in bud stage. Look for plants with strong stems, healthy dark green foliage and no wilting. After purchase, it is advisable to take the plant home as soon as possible and not leave it in the car while doing other shopping.

Remove any plastic wrapping on arrival at home.

To make your poinsettia last, give it as much natural light as you can, six hours of indirect light per day, avoiding hot south-facing windows. Water the plant when the soil in the pot feels dry, usually once a week. To water the plant, remove it from the foil decorative cover and water until the water drains out of the pot. Avoid wetting the foliage. Allow the plant to drain well before returning to placement with a saucer under the plant.

Overwatering is a common plant killer. Keep the plant away from heat sources, drafts and temperatures under 45 degrees or above 80 degrees. Optimal temperature range for the plant is 65 to 70 degrees. The plant is blooming, but not growing at this time of year, so fertilizer is not needed. Poinsettias cannot tolerate frost and will be killed if temperatures are below 50 degrees for an extended period. For this reason, poinsettias are decorative holiday house plants.​

The red poinsettia remains a popular favorite, but new varieties continue to be developed to add excitement to holiday decorating. The new colors include pinks, orange, white and variegated colors.

Enjoy this cheerful, brightly colored house plant as the days turn gray and cold.

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