Tidewater Gardening - December 2011

Poinsettia Pointers and Alternative Holiday Plants

by

K. Marc Teffeau

The poinsettia continues to be he most popular Christmas flower in the U.S. Over 70 million plants, worth over $250 million dollars a year are sold during a six week period between November and December. Since the poinsettia’s introduction into the marketplace back in the 1800s, plant breeders have gone beyond the traditional red and have developed a number of different colors to add to the basic red. White, pinks, white/pink combinations, salmon and even a yellow poinsettia are being grown and sold.
Poinsettias are also a somewhat difficult plant to grow in the greenhouse because the producer has to not only control the growing temperature, both day and night, but also the amount of light to which the plant is exposed. A miscalculation can result in the plants not coloring up until after Christmas, or prematurely before the season. Poinsettias can also have their share of insect and disease problems in the greenhouse.
The success and popularity of the poinsettia as a holiday flower wasn’t always the case. The poinsettia isn’t, as some believe, a native of the Holy Land, but rather it grows wild as a shrub in Central America up through Florida. It was introduced into the United States in 1825 by Joel Robert Poinsett, our first ambassador to Mexico. The flower was named in his honor.
Poinsett sent plants home to his own conservatory in South Carolina and to his daughter in Philadelphia. December 12th is Poinsettia Day and was declared in honor of the death of Poinsett on December 12, 1851.
There is a legend in Mexico that tells how the plant became established. When the Toltec elders were slain defending he temple of Quetzalcoatl against the invading Aztecs, the Toltec youth donned their discarded brilliantly-feathered headdresses, determined to carry on the battle. Quetzcoatl transformed the feathers into tongues of flames that terrified the Aztecs. They fled the battle and when the Toltec boys placed the headdresses on the ground, poinsettias sprang up around the temple in their honor.
The poinsettias was first propagated and sold in this country by Robert Buist, one of Philadelphia’s early nurserymen. By the late 1800s the plants were being grown by florists for Christmas, but they were still somewhat a rarity at the turn of the century.
The early poinsettias were “contrary” plants and difficult to grow. Any change in the environment and they dropped their leaves. In fact, florists used to plant ferns with them so that when the leaves fell off the poinsettias their stems wouldn’t look so bare.
Development of this exotic plant has continued and today’s poinsettias are a great improvement over those of only a few years ago. They are vigorous growers, produce multiple blooms and hold their leaves. Their flowers las long after Christmas.
The flower of the poinsettia is an example of the great versatility of nature. The red “petals” are really leaves or bracts. They are green at first, then turn red as the real flowers develop. The true flowers are inside the knob-like bumps in the center. Each of these bumps – called a cyathium – contains a single female flower surrounded by a cluster of male flowers. Each cyathium also has a prominent yellow gland that produces nectar. This combination of nectar and the surrounding brilliant red bracts is an irresistible attractant for insect pollinators in nature.
To get the maximum satisfaction from your Christmas poinsettia, make sure that it doesn’t dry out, but at the same time, don’t keep it sitting in water. Each day, test the soil for proper moisture content. While the poinsettia is in flower it requires a considerable amount of water. Keep the soil moist but not soaking wet.
Poinsettias don’t like drafts. Keep them away from an outside door where they will receive a blast of cold air each time to door is open. Also, keep the plant away from hot air vents.
Since the poinsettia is a warm-weather plant, it is important that the room be kept at 70 to 75 degrees. Keep the plant in bright, indirect sunlight, but don’t place it in a sunny window for more than a few hours a day.
Some people like to try and keep the plant over the holidays and try to get it to re-bloom next Christmas. This can be done but it is a challenge for the home gardener. Poinsettias are photo-thermo-trophic, which means that their flowering response depends on being exposed to both specific temperatures and hours of light. To get the plant to re-flower next Christmas, you will need to provide the right temperatures and daylight hours.
Have you ever thought of poinsettias as cut flowers? They can be used in cut flower arrangements if they have been treated properly. As soon as half of the small yellow flowers in the center of the colorful bracts have opened, cut the stems to a desired length. After cutting the stem, you will notice white latex oozing from the latex tubes. You will need to quickly cover the ends of the stems. To prevent further loss of the latex and to prolong the vase life of the flower, dip the cut ends of the stems into boiling water, approximately two inches deep.
The boiling water coagulates the latex in the tubes and forces out any that may have been pulled into the base of the water-conducting cells. When this treatment is not given, the latex apparently plugs the water conducting tissues causing the flowers to wilt soon after cutting.
In addition to coagulating the latex, searing permits water to be absorbed through the sides of the stem, increasing efficiency. For some latex-sensitive individuals however, exposure to the stem latex can cause an allergic reaction. Because of this, it is suggested that you not give a poinsettia to a latex-sensitive person.
Every holiday season, the urban legend resurfaces that poinsettia leaves are poisonous if you eat them. You will often find them on lists or poisonous houseplants, but they are not considered dangerous. Toxicity research done at Ohio State University a number of years ago debunked the myth. However, I would not make the Christmas dinner salad out of them, though. The origin of this myth could be found in the fact that many plants of the spurge genus are indeed toxic.
If you are looking for an alternative Christmas plant, there are other plants that can serve in the role of “holiday plants.” Many of them are available at florist shops, garden centers, supermarkets and greenhouses of the Christmas season.
One such plant is the Amaryllis. This flower can be bought in any stage of growth from a single bulb all the way to the semi-opened or “puffy bud” stage. If you purchase one, be sure that one third of the bulb is above the soil line in the pot. Place this bulb in a sunny, warm location and watch the leaves unfold and the flower stem stretch. Keep the growing medium that the bulb is in on the dry side, don’t overwater it. Since the amaryllis is a tropical plant, keep the room temperature above 60 degrees and in high intensity light. If the plant does not receive enough light, its leaves and flower stem will stretch or elongate too much and fall over.
It takes an average of four weeks from the time the bulb is planted until it flowers. When you see the first flower bud begin to swell and turn color, it will only be another day or two until it completely opens. As a general rule, the larger the circumference of the bulb, the more flowers you will get. Larger bulb sizes (10 inches or more in circumference) will give you at least four flowers. Amaryllis flower colors range from white and pink to orange.
Kalanchoes are another holiday plant that is tough and can endure in our homes for a couple of months during the winter. If you compare the leaves of the kalanchoe to the common jade plant, you will notice a resemblance. They both have thick, firm, fleshy leaves. However, the kalanchoe’s are more flattened and tightly packed than the jade plant.
The kalanchoe likes it hot and dry. If you need a plant that can take being in a hot room (like where the wood stove is located) or drafts from the nearby radiator or heat vent, this plant will do well. You can even forget to water it sometimes, however if you do flowering will be reduced. When choosing your kalanchoe, look for a minimum of two to three flower clusters on a four inch plant and four or five on a six inch plant. Make sure that the plant has lots of color and little or no dead flowers.
If you, or someone you know, likes begonias, consider getting a Rieger begonia. They look very similar to the garden tuberous begonias. Reigers are relatively tolerant of sun exposure and temperature. They do prefer to be slightly moist, but not sopping wet. Single and double flowers can be found on the same plant. The measure of a high-quality plant will be one that is at least half covered with flowers.
African violets are always popular as a holiday gift plant. Have you considered purchasing a close relative – the Gloxinia? They are large, low growing and spreading plants with small, trumpet shaped flowers. You can treat gloxinias like African violets. Avoid high-intensity, direct sunlight and water them from the bottom of the pot with warm water. Never water African violets or gloxinias from the top of the pot as this will encourage stem rot in the plant. Keep the soil moist but not waterlogged and avoid cold and hot drafts
Look for plants that have at least three to five open flowers and at least that many more buds growing in the center of the plant. A six-inch gloxinia will have a dozen or more buds and will continue to flower for three to four weeks if properly cared for. If you allow the plant to dry out or you locate it in a room that is too dark, the flower buds will fall off. Gloxinias come in a wide flower color range of whites, purples, pinks and bicolors.
Happy Gardening and Happy Holidays!