Let’s play true or false with the popular poinsettia, starting with ‘Is it poisonous?’

A great garden in a small space

Jake and Sharyn Schaffer's patio garden in San Luis Obispo makes the most of the small landscaping space.
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Jake and Sharyn Schaffer's patio garden in San Luis Obispo makes the most of the small landscaping space.

Odd things, those urban myths. It’s amazing how they get started, and it’s funny how they’re almost impossible to stop. And nowhere in horticulture is that any more evident than with poinsettias, Euphorbia pulcherrima. But there are also some fun facts assigned to this plant, and I thought you might enjoy seeing a few of them.

Poinsettias are not poisonous!

I’m a graduate of Ohio State, and the research was done there back in the 1970s. 40 years ago. But news apparently travels slowly. They are not poisonous! Fact-check it on Along with other interesting data, they cite the American Medical Association’s Handbook of Poisonous and Injurious Plants, saying that it “lists nothing more than occasional vomiting as a side effect of ingesting otherwise harmless poinsettia leaves.” Same thing for pets.

All poinsettia flowers are yellow

That’s actually true. The brightly colored “petals” for which we buy and give these beautiful plants are actually modified leaves, not parts of the true flower at all. They’re called “floral bracts.” The true poinsettia flowers are those pea-sized, golden yellow, taco-shaped structures filled with honey-like goo that you’ll find at the growing tips of the stems.

Poinsettias are actually shrubs or small trees

But that’s because they come from tropical regions where temperatures never drop below freezing. The plants keep growing and growing until they’re 10 or 12 feet tall and wide. Truth is, if you set this year’s poinsettia out in your yard in early April, and if you give it all the water and fertilizer it needs, it might grow as high as your eaves by the time the first freeze arrives next November. But do read on.

The larger the poinsettia plant, the smaller its floral bracts will be

That’s because there will be so many more of them. That 10-foot-tall plant might have several hundred bracts, but each would be only 4 or 5 inches across. By comparison, a well-grown plant in a 6-inch flowerpot may have a single bract that’s 12 inches tip-to-tip.

When are poinsettias uprooted?

And can you imagine that the plant that you have in your home was nothing more than an unrooted cutting just 110 days ago! Growers have perfected the science of growing this fabulous plant. Rooted cuttings are potted in August, grown pot-to-pot for a few weeks, then placed at their ultimate spacing with watering tubes inserted into each container. No crop that greenhouse growers produce is any more spectacular any more quickly.

Poinsettias are photoperiodic

Hang onto that term. It refers to a plant that blooms when nights reach a certain length. Flowering hormones build up in the growing tips, and the plants start producing their buds. Other examples: chrysanthemums, kalanchoes and Christmas cacti. If you want to keep these plants from blooming, turn on the lights in the middle of the night. If you want to bring them into bloom at some unusual season, pull black shade fabric over them to give them artificially “long nights.” Using that technique, there was a brief and unsuccessful attempt 30 or 40 years back to feature white poinsettias as an Easter crop, since they’re much easier to grow and bring into bloom than lilies, but the world just wasn’t ready for poinsettias that soon after Christmas.

The pronunciation

Not to be snobbish, but you may be mispronouncing the plant’s name in the first place. It has four syllables (poin-set-ee-uh), not three. For some unexplained reason, the “i” is forgotten by many. Even my horticultural friends are occasionally caught taking the shortcut.

Poinsettias are named for Joel Roberts Poinsett

You may have read that before, but there is so much more to know about this very bright man, a member of the privileged society of Charleston, South Carolina. His father was a wealthy physician who wished for his son to become a successful attorney. The young man traveled extensively in Europe and the Middle East, and then into Russia and eventually through South America. He was nominated and elected to the South Carolina state legislature, then the U.S. House of Representatives. Working under President James Monroe he became the first Minister to Mexico and in 1828 signed the first treaty between the United States and Mexico. It was during his time in Mexico that the avid gardener saw the plant that would eventually be named for him and sent samples of poinsettias back to the States.

Keep it around after Christmas

Want to get the longest possible enjoyment out of your poinsettia this Christmas? Don’t let it wilt. Stick your thumb down into its pot morning and evening, and when the soil begins to feel dry to the touch, soak it thoroughly. When we water a wilted poinsettia, its leaves will pop back up and look normal within an hour or two. However, three or four days later the bottom-most leaves will start to turn yellow and fall. Don’t water it if it’s still wet, but for certain don’t let it dry out.

Neil Sperry hosts“Texas Gardening” from 8 to 10 a.m. Sundays on WBAP/820 AM. Reach him during those hours at 800-288-9227. Online: