How to Grow Poinsettias for Christmas
Everyone loves colorful poinsettias during the holiday season, but once the holidays have passed, even if you have kept your plant alive, it won’t bloom again the following December. Once you understand why the bright red flowers develop, it’s easy to force your poinsettia to bloom year after year.
What are poinsettias?
Poinsettias are a shrub that grows from 2 to 13 feet in height. They are native to Mexico. In the U.S., they are hardy only in zones 9 through 11, so they must be brought indoors during the colder months of the year. When you purchase your plants during the cold holiday season, make sure that they are wrapped up well to prevent them from getting chilled. Carrying them unwrapped from the store to your car and home will result in the loss of leaves. Once you have arrived home with your wrapped plants home, unwrap them immediately. If left wrapped too long, the stems of the leaves and bracts will begin to droop.
The large red bracts of poinsettias are often mistaken for flowers but they are actually leaves. They can be red, orange, pale green, cream, pink, white, or marbled. The color is created through the process of photoperiodism, meaning they require a specific number of hours of darkness each night to change from green to red or other colors. The flowers are actually the tiny yellow structures found inside the colored bracts.
How did poinsettias become associated with Christmas?
The association with Christmas began as a legend in 16th century Mexico. The legend tells of a young girl named Pepita or Maria who was so poor that she couldn’t afford to buy a gift to celebrate the birthday of Jesus. An angel appeared to her and told her to gather weeds from the roadside and place them at the altar of her church. Miraculously, the weeds sprouted red flowers which became poinsettias.
In the 17th century, Franciscan friars in Mexico began to use poinsettias as decorations for Christmas. In their eyes, the leaves growing in a star shape represented the Star of Bethlehem and the red color of the bracts represented Jesus' blood that was shed to cleanse the sins of believers.
How did poinsettias become so popular in the U.S.?
It all started with an immigrant from Germany named Albert Ecke. He became fascinated with poinsettias and began selling them at a street stand in Los Angeles. His son, Paul Ecke, developed the technique of grafting two varieties of poinsettia together to produce bushier plants. His son, Paul Ecke, Jr, sent free plants to television stations to use as set decorations from Thanksgiving to Christmas. He even appeared on popular shows such as The Tonight Show and Bob Hope’s Christmas specials to promote the plants.
How do I take care of my poinsettia after Christmas?
During the holidays and through the winter, keep your plant in a sunny window. Ideal air temperature is 60⁰F to 70⁰F. Higher temperatures will cause the plant to prematurely drop its colorful bracts. Keep it out of drafts. The plants are very sensitive to cold. If you are able, you can prolong the life of the colorful bracts by moving your plant into a cool room that 55⁰F to 60⁰F at night.
Water only when the soil feels dry. Too little water will cause the leaves to drop. Too much water will cause the leaves to turn yellow and then drop. Fertilize your plant using a soluble houseplant fertilizer as directed on the label.
In late February or early March, prune your plant back to 4- to 6-inches leaving between one and three leaves on each stem. Continue with the same watering and fertilization schedule.
In the spring, once nighttime temperatures are consistently above 50⁰F, you can bring your plant outdoors. Before you do so, you might want to repot it if it has outgrown the pot it came in. Outside, it will need to grow in a semi-shady location. Poinsettias are native to Mexican forests. At the end of July, you should prune your plant again. Cut it back to 4 inches, leaving one to three leaves on each stem, and begin fertilizing every two weeks.
In the fall, you will need to bring your plant back indoors when the nighttime temperatures are consistently below 45⁰F. You can bring it outdoors during the day if you like. Continue the biweekly fertilization schedule.
The secret to making a poinsettia bloom at Christmas
Your poinsettia will only display colored bracts if it experiences complete darkness for at least 12 hours per night for 10 weeks. It cannot be exposed to any kind of light such street lights, car headlights, TV’s, computer screens or even light under the door. Commercial greenhouses achieve this using opaque shade cloths to cover their plants at night. At home, you can use a box large enough to cover your plant completely.
Count back ten weeks from the date that you want your poinsettia to begin blooming, usually the end of September or beginning of October for an early to mid-December blooming. For best results, place the box over your plant at 5 pm (or whenever you return from work) and leave it there until 8 am (or whenever you leave for work) every day until color begins to show in the bracts when you remove the box in the morning.
And that’s it! That’s the whole secret to making a poinsettia bloom every year at Christmas. Simple really once you understand why the bracts change color.