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Ask the Placer County Master Gardeners: Keep poinsettias away from cold and drafts

By: Gay Wilhelm and Trish Grenfell
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Question: What’s the best way to take care of a holiday poinsettia? Answer: Poinsettia, or the Latin name Euphorbia pulcherrima, is the best selling potted plant in the nation. It was named for Joel Poinsett, the first U.S. ambassador to Mexico who loved botany. In December 1828, as Poinsett was roaming the Mexican countryside, he saw these tall shrubs, shipped cuttings to his greenhouse in North Carolina, and the rest is history. Today more than 150 million potted poinsettias in every color and size are sold in more than 40 countries. The true flowers growing at the top of this plant are tiny, yellow and rather inconspicuous. The plant’s beauty derives from its colorful bracts that are petal-like modified “leaves.” The length of time your poinsettia will bloom depends upon two things: choosing a young, healthy plant and how you and/or the seller care for it. Some varieties may last for months. Poinsettias, like fruit, can be overripe. When selecting, look closely at the tiny yellow or green berries in the center of the bracts (the true flowers). If they are tight, they are still fresh. In other words, choose a plant that hasn’t shed pollen yet. Look for yellow pollen on the petal-like red and green bracts. Poinsettias showing pollen grains don’t stay nice as long as those that haven’t yet released pollen. Also pay attention to the conditions where poinsettias are being sold. Poinsettias offered in stores during the holidays have been raised in a greenhouse at 60 to 70 degrees, in high humidity and maximum sunlight or growing lights. Store displays that mimic these growing conditions closely may contain healthier poinsettias than those for sale in hot, dry, and low-light conditions. Choose poinsettias with deep green, not yellowish, leaves. Yellowing of foliage may indicate insufficient light, over-watering or lack of nitrogen. Low temperatures, even for a few minutes, will damage the red bracts and leaves. Don’t leave the plant in a cold car to do the rest of your shopping. Unwrap the pot from any foil covering or at least poke drainage holes in the foil. Place the plant in a sunny window, but do not allow the leaves to touch a cold window. Be sure to keep the poinsettia from warm or cold drafts. Cold winter winds near doors will damage a plant as well as warm heat registers. Ideal temperatures of 60-70 degrees and nighttime temperatures of 55 will prolong the plant’s life. If possible move the plant to a cooler room at night. Check soil daily for moisture and if dry, water. If you decide to keep the poinsettia after the holidays, apply a houseplant fertilizer such as fish emulsion according to enclosed directions. Contrary to popular belief, poinsettias are not poisonous. Have gardening questions? Call the Master Gardener hotline at (530) 889-7388.