If you’re like me and LOVE beautiful, red-flowered poinsettia plants at Christmas but avoid taking them in because they unfailingly die slow, painful looking deaths in your house after the holidays are over, here’s some helpful info from:http://www.helpfulgardener.com/container/2003/poinsettia.html:
REBLOOMING AND CARING FOR YOUR POINSETTIA
Poinsettias are a widespread Christmas tradition both for gift-giving and holiday decorating. Yet many of these lovely plants end up in the trash once the holidays are over. Your poinsettia will not only make a beautiful indoor plant all year long, but can also be coaxed to bloom again each year in time for Christmas.
Poinsettia Legend and History
Poinsettias (euphorbia pulcherrima) are native to Mexico and Central America. The Aztecs called it cuetlaxochitl. Poinsettias were introduced in the United States in 1825 by Joel Poinsett, the first U.S. ambassador to Mexico, and quickly caught on as a popular Christmas plant.
Poinsettias have thin, pale green leaves. When in bloom, they display brightly colored bracts (red, pink, or white) on the top of each stem. Although many mistakenly think that these bracts are flower petals, the actual flowers are the tiny yellow clusters found at the center of the bracts (Bract are simply leaves masquerading as petals). Another common misconception is that the plant is poisonous. Like most euphorbias, the sap is a little caustic and may cause skin irritation, and certainly indigestion if digested, but if you’re going to knock the hubby off for the insurance money (there’s a cheery holiday thought…), find another plant.
Forcing Poinsettias to Bloom
Poinsettias bloom in response to shortening daylight hours. If you wish to coax your poinsettia to bloom in time for the holidays, you will need to put the plant in total darkness for at least twelve hours (fourteen is better) each night for approximately ten weeks (this also applies to forcing Christmas Cacti to bloom). Late September or early October is a good time to begin this regimen. You can place your plant inside a box, a cupboard, or a closet to achieve complete darkness. Be sure to bring your plant out during the day and place it in a bright, sunny spot. After it flowers, gradually decrease the water until the bracts all drop, then allow the plant to dry out completely (like many of the euphorbias, this is a desert plant). Store in a place with cooler temperatures (50 degrees); remember we are trying to recreate a Mexican Winter, so a 50 degree basement or garage makes a fine location.
When it really begins to warm up again (Late May for us, but just so long as you’re around 50 degree evenings), repot your mummy in the same pot with fresh soil and start to water again (we stopped gradually and that’s a good way to start) and fertilize (also gradually). Around August, cut the plant back by a third and make a decision. Do we want bushy with small flowers or shrubby with big flowers (my pick)? If we choose the latter we cut the plant back to three to five stems and grow it out (remember gloves if you have sensitive skin). A poinsettia can look quite lovely when planted with foliage plants with contrasting leaf color, shape, and/or size. Don’t prune your plant any later than September, however, if you wish to force it to bloom for Christmas.
Poinsettias like lots of bright, indirect sunlight and prefer humid conditions (so you may want to mist your plant if your home is very dry due to heating or climate). As for watering, let the soil dry out between watering. The soil should be dry to the touch. Also, be sure not to let the plants pot stand in water at the plants base or saucer(A layer of pebbles in the bottom of the tray keeps the plant out of the water and increases the humidity around the plant). Poinsettias are sensitive to extreme temperature, so don’t place your plant next to a heater or near a drafty window or doorway. A daytime temp of around 65 degrees and nights around 60 degrees will provide perfect conditions for your poinsettia. Whitefly can sometimes be a pest for this plant; check your purchase closely. If you pick it up, and things fly, and they’re white, well, there it is. Pretty easily taken care of with insecticidial soap or my favorite indoor pesticide, pyrethrine (made of daisies; it’s organic and safe if you don’t drink it).
Poinsettias are a beautiful holiday tradition, but your enjoyment of these charming plants does not have to end when the Christmas tree comes down. With just a little effort, you can derive pleasure from your poinsettia all year long and bring it to bloom for many holiday seasons to come.