Poinsettias fill homes with holiday cheer, but when the Christmas decorations are packed away, the plants also go. Some folks have no problem sending these festive beauties to the trash can. Others treat them like regular houseplants until the colorful leaves drop off in spring. But a few people keep their poinsettias so they can bloom next Christmas. It isn’t easy, but the reward is another beautiful plant.
To “rebloom” a poinsettia, follow these simple rules.
• After Christmas, continue to grow the poinsettia as a houseplant. Keep it evenly moist and in fairly bright light. In February or early March, cut back each of the stems to 4 to 6 inches in height above the soil line to promote new growth. In May, repot the plant into a slightly larger pot. Periodically turn the poinsettia to promote a more uniform shape. When the danger of frost has passed and night temperatures are above 60 degrees, the plant can be placed outdoors in a shady location.
• To achieve optimum growth during the summer months, water regularly and fertilize every two to three weeks with a complete fertilizer such as 10-10-10.
• Prune or pinch out the top one-fourth inch of the growing shoots every three to four weeks to encourage branching. Two or three large leaves should be left below the pinch. Continue pruning until mid-August to achieve a beautiful shape for the holidays.
Flowering is “photoperiodically” induced in the poinsettia. This means that flowers begin to form when the days are a certain length. The poinsettia is a short-day plant. Without long nights, this plant will continue to produce leaves but will never flower. For short-day plants to produce flowers, they must experience days with less than 12 hours of daylight. Most varieties of poinsettias require 8 to 10 weeks of shortened days to flower. Therefore, to have the plant in full flower by Christmas, keep it in complete darkness between 5 p.m. and 8 a.m. from the first part of October until Thanksgiving. A closet or cardboard box will keep the plant in darkness during those hours, but remember to put the plant near a sunny window in the daytime. For full color before Dec. 25, short-day exposure needs to start in early October. If a different target date is desired for full color, adjust the onset of short day exposure 8 to 10 weeks before the target date.