Posted by Brent Wilson on 9/12/2016 to Container Gardening
During the holiday season, we see poinsettias everywhere. Many of us buy a plant for decorative touch or as a gift for someone we are visiting. The poinsettia industry has grown around this holiday tradition. Today, poinsettias are one of the most important floricultural crops produced in the United States grown primarily as a potted plant for the Christmas season.
If you care for a poinsettia plant properly you can keep it for many years and make sure it "flowers" during the Christmas season.
First, a little about poinsettias...
Flowers or Foliage?
The poinsettia, Euphorbia pulcherima, does not have showy flowers. Rather, the bracts (modified leaves) create the splash of color during the holiday season while the true flowers are small and insignificant (unless you are another poinsettia). The colorful foliage of poinsettias is a response to photoperiod (hours of daily sunlight). There are so many shapes, sizes, and colors of poinsettias available that a complete column could be written on that subject alone.
Are Poinsettias Poisonous?
Contrary to popular belief, poinsettias are not poisonous. Ohio State University conducted research on the poinsettia plant effectively disproving the charge that the poinsettia is harmful to human and animal health. Of course, the poinsettia, like all ornamental plants, is not intended for human and animal consumption. As pretty as they might be on a plate or mixed with leafy vegetables in a salad, they'd only soil the dish!
Caring for a Poinsettia Plant
Here are some tips to keep your poinsettias looking perky and colorful well beyond the holiday season:
Poinsettias thrive on bright, sunny natural daylight; at least six hours daily is recommended. Placement near a sunny window is ideal.
To prolong the bright color of the bracts, temperatures ideally should not exceed 70 degrees F during the day, or fall below 65 degrees F at night. Be sure to avoid placing the plants near drafts, fluctuating air currents, excess heat and dry air from appliances, fireplaces or ventilating ducts. Chilling injury will occur if poinsettias are exposed to temperatures below 50 degrees F. Frost ensures certain death of the plant!
Poinsettias do best with a moist soil condition, not too wet and not too dry. Water the poinsettia thoroughly when the soil surface feels dry to a light touch. The best indication of a thorough watering is when the water begins to seep through the drain holes at the bottom of the inner pot. Be sure to discard any excess water, as poinsettias left sitting in water may suffer from permanent root-rot damage.
It is not necessary to fertilize your poinsettias when they are in bloom during the holiday season. However, after 6-8 weeks, a balanced, all-purpose household plant fertilizer mixed one-half strength will help maintain the rich, green foliage color and promote new growth. Repeat once more in another 6-8 weeks.
How to keep a poinsettia growing until the next season
It is possible to keep a poinsettia growing until the next season, however you will need to follow these tips to be successful:
First, avoid over-watering your poinsettia. Allow soil to dry out a little between waterings. Consistently wet soil can be a killer.
At the end of April or early May, when the bracts (colored leaves) age and begin to turn a muddy green, cut the plant back to about 8 inches in height. The amount you cut from the top will depend on the shape of the plant. After you cut the plant back, it will look bare. This is not the plant's most attractive state, but by the end of May you will see vigorous new growth as the plant develops more lush green foliage. Keep the plants near a sunny window or place them outdoors where they will receive a good amount of sunshine.
Continue to water the plants regularly during the growing period. Fertilize every 3 to 4 weeks throughout the spring, summer and fall. Use a well-balanced water soluble fertilizer mixed at half-strength.
Around June 15th you can transplant your poinsettias into larger pots, about 2 to 4 inches larger than the original pot. Fill empty space in the new container with a professional potting mix. Immediately after transplanting, be sure to water thoroughly.
Starting October 1, the plants must be kept in complete darkness for 14 continuous hours each night. Moving the plants to a dark room or placing a large box over them can accomplish this. During this period, the plants require 6 to 8 hours of bright sunlight and night temperatures between 60 and 70 degrees F. If the temperature is too high or too low, the setting of the flower buds may be delayed or halted. The blooming process may also be delayed or disrupted by any stray light that may shine near the plants during the critical darkness period. Keep this up for 8 to 10 weeks for full color development.
If this sounds like a lot of work, it is...and it certainly gives us a healthy respect for those who commercially grow poinsettias!
If you did everything right, the plants will naturally come into full bloom during November or December, depending upon the flowering response time of the particular variety. This can be tricky to do outside of a controlled greenhouse environment, because any stray artificial light, such as that from a street light, pool light or household lamp could delay or halt the re-flowering of the plants.
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