Poinsettias fill homes with holiday cheer, but sadly, when the Christmas decorations are packed away, the plants tend to go.
Some folks have no problem sending these festive beauties directly to the trash can. Others treat them like a regular houseplant until the colorful leaves drop off in spring. But a few will hold onto their poinsettias with visions of reblooming them. It isn’t easy, but the reward is a beautiful poinsettia for next Christmas season.
To rebloom a poinsettia, follow these 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 stem to 4 to 6 inches above the soil line to promote new growth.
In May, put the plant into a slightly larger pot and periodically turn it to promote a more uniform shape. When all 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 summer, water regularly and fertilize every two to three weeks with a complete fertilizer such as (10-10-10).
Prune or pinch out the top quarter 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-Augus.
Flowering is photoperiodically induced in the poinsettia. This means 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 never flower. For short-day plants to flower, they must have less than 12 hours of daylight.
Most varieties of poinsettias require eight 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.
During this period, any kind of light exposure between 5 p.m. and 8 a.m. will delay flowering. A closet or cardboard box will keep the plant in darkness, 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 eight to 10 weeks before the target date.