How to Make a Poinsettia Rebloom

— Written By and last updated by Extending the Poinsettia Season-1

It’s the Christmas season once again, and we are all excited about seeing family and friends, eating holiday meals and decorating our homes in festive ways. If you’re like my grandmother, you’ve tried to save those beautiful poinsettias from last year, but they never will turn red. To most people, it’s a mystery as to why a plant can be so pretty and then never look that way again. Well, by the end of this article you will know how to make those poinsettias bloom just as pretty as they have in the past.

Poinsettias are phototrophic, which means that–just like all plants–they get their energy from the sun. The only difference is that this weird little plant takes the need for proper light to a different level. Poinsettias bloom based on the length of day. When the day length is correct the plant will bloom, and the bracts (the red part) will begin to color. North Carolina is not the native range for the poinsettia, of course, so we have to take a little extra step to help it to reach this blooming stage. 

 In order to force our plants to bloom, we need to make sure that the plant has a steady 14 hours of darkness and 6-10 hours of bright sunlight. The darkness is imperative to get your plants to rebloom. Even a slight interruption in the darkness can cause the plants to not bloom. The best way to make sure they are getting enough darkness is to place the plant in a closet and set a timer for 14 hours each day. In this process do not open the door to that closet at all. If this is done correctly your poinsettia should begin to color up in about 6-8 weeks and be in full bloom in 12 weeks. Counting backwards from Christmas, that means we must begin our darkness process (or what is technically known as a photoperiodic treatment) around October 1 for the plants to be showing their full glory by the holiday.

After the Christmas season, there are a few other things you can do to keep your poinsettia in the best shape possible:

  • Reduce watering of your plant,  but do not let the stems shrivel. This will allow the plant to enter a dormant state so you can store it for the winter.
  • In the spring, after all frost danger has passed, cut the poinsettia back to 6-8 inches in height and repot the plant into a bigger pot. Place it outside in a partly sunny location that is protected from the wind.
  • As the plant grows, pinch the new growth to keep the plant compact and bushy. As we reach the fall you can begin your photoperiodic treatment for yet another year of great color from your favorite poinsettia.