November 30, 2013
Poinsettias (Euphorbia spp.) are the most popular holiday houseplants. Poinsettias are native to Mexico and were introduced to the United States by Joel Roberts Poinsett, the first U.S. Ambassador to Mexico and an American botanist. Poinsett began sending these brightly colored plants to American botanical gardens in 1828.
Poinsettias are a great commercial product, contributing more than $250 million to the U.S. economy every year. California is the number one producer, with Ohio being the fifth largest Poinsettia producer.
More than100 varieties of Poinsettias are available in colors of red, salmon, pink, orange, white, and yellow. What many people believe to be the blooms of the plant are actually modified leaves called bracts. In order for the bracts to change color to the vibrant shades we know and love, the plant must experience at least 12 hours of darkness for five consecutive days. Once the photoperiodism is complete, the plant requires bright sunlight to maintain its color. The actual flowers of the Poinsettia are the yellow cyathia at the center of the colorful bracts. These tiny flowers carry the plants pollen. When the pollen is released, the plant will drop its leaves and colorful bracts. For longer lasting color, choose a plant with little or no pollen showing. For more information about how to care of your Poinsettias, read the OSU Extension Fact Sheet HYG-1248-96 at http://ohioline.osu.edu/lines/facts.html.
A broken stem of the Poinsettia will ooze a bitter sap which, if eaten in very large quantities, could be a health hazard, but the taste is so offensive that people and pets would not eat enough to experience adverse effects. Still, it is recommended to keep Poinsettias away from children and small house pets, such as puppies and kittens.
Another popular holiday houseplant is the holiday cactus. These plants actually are succulents, not true cacti. In their natural habitat, they live in trees as epiphytes (non-parasitical plants that grow on another plant). Three holiday cacti are common: Christmas Cactus (Schlumbergera bridgesii), Thanksgiving Cactus (Schembergera truncata), and the Easter Cactus (Rhipsalidopsis gaertneri).
The Thanksgiving cactus is the plant that you see blooming in stores in November and December. The leaf margins have two to four saw-toothed projections pointing upward on the side of the stem. Its blooms are red, lavender, salmon-orange, or white, and its pollen-bearing anthers are yellow.
Christmas cacti bloom from Christmas through March. The leaf margins have four rounded scallops along the edges. Typically the blooms are red or white, and the anthers are purplish-brown. Easter cacti bloom from March through May and sometimes in the fall. Their flowers are pink or red, and the leaf margins are smoother than the other seasonal cacti. They exhibit brownish, hair-like bristles at the tips.
These succulents prefer a humus soil mix that is evenly moist. They like to be a little root-bound, so repot every three years. These plants need at least 13 hours of darkness to trigger the blooms. Once the blooms pop, place in bright daylight. Do not over water, and keep nighttime temperatures cool (55-65 degrees F). Each bloom will last several days, and the plant will bloom for several weeks. Feed your succulent with a houseplant fertilizer after the blooming period.
If you pinch the plant back in the summer, it will prompt branches, which will result in more blooms for your enjoyment. It is easy to propagate these plants by making cuttings of the flattened stem sections (phylloclades). You can root the cuttings directly in moist, humus soil.
A third popular holiday houseplant is the Amaryllis (Hippeastrum hybrids). These great indoor plants love a sunny window and can re-bloom year after year. This plant begins from a bulb, which needs small amounts of water until the stem begins to emerge, then water it often. When the flowers fade, cut the stalk back to two inches above the bulb, keep it in a sunny spot and water it regularly. Feed it with liquid fertilizer every two weeks. This is the growth phase, and proper care will boost next year’s flower production.
You can place the plant outside in the spring and summer, making sure to keep it well watered. Bring it inside before the first frost and store it in a cool, dark place for six to eight weeks without water. After the bulb rests for a couple of months, repot it, and place it back in a sunny window and wait for the new growth to appear. The bulb may produce up to three stalks with single or multiple blooms on each stalk.
The Poinsettia, holiday cacti, and the Amaryllis can bring cheer and color to your home during the holiday season.
Robin Volker is a Delaware County OSU Extension Master Gardener Volunteer