Odds are you have a poinsettia in your home for the holidays. In the United States, poinsettias are grown in greenhouses and programmed to bloom in time for Christmas. Try to emulate the bright light and balmy 70 degrees the greenhouse has to offer in your home so your poinsettia will survive the holidays. Keep the soil moist but don’t let the roots sit in water. Make sure the pot has drainage holes. If it is in that decorative foil, either remove foil or cut bottom out of foil so excess water drains out.
After the holidays, grow it as if it were a houseplant. With luck, you may be able to see colored bracts (the “flowers”) again next year. Keep the plant in bright light and 70 degree temperature. In the spring, cut the stems back about half the length. Keep indoors or put outdoors in the warm summer months. Apply a houseplant fertilizer and make sure the plant does not dry out. In June, transfer into a slightly bigger pot. In September bring the plant back indoors. To induce flowering, give the plant bright light each day and fourteen hours of uninterrupted dark each night beginning in early October (as in cover with a box or put in a closet). Keep the soil moist but stop fertilizing. The color should form on the bracts in six to eight weeks.
Poinsettias are odd plants out in the garden. Because no one likes to prune them back, they get very tall and lanky, with scrawny blooms up high. It sort of makes one wonder why they were ever selected to be grown as potted plants. I mean, if I saw something like that out in the wild in Mexico, I would have just left it there. Yet, if pruned back, they can get a bit fluffier, with nice color right after Christmas. Of course, they never look like they did when potted, but they are cool in their own way.