Like many seasonal plants, the poinsettia is usually simply disposed of after flowering. It’s not that difficult to get it to bloom again. We’ll tell you what to do about it.
Poinsettias (Euphorbia pulcherrima) are now available in every hardware store during Advent. After the holidays, they usually end up in the trash or on the compost. The reason: Most hobby gardeners fail to get the plants to bloom again in the next year. It’s not that difficult at all if you deal with the native living conditions of tropical flowering trees and know the demands of poinsettias.
How do you make a poinsettia bloom again?
- Reduce the watering from the end of February to April so that the plant enters a dormant period. At the end of April, you cut them back to a height of 15 to 20 centimeters and slowly increase the watering quantities again.
- Place the poinsettia in a bright place and provide it with liquid flower fertilizer every week until mid-September.
- From September 22nd, the poinsettia will be brought into a room that is only illuminated by daylight. The flower formation is complete after about eight weeks.
Why don’t poinsettias bloom?
The reason for the supposed blooming laziness is a phenomenon called photoperiodism. Like many tropical plants, the poinsettia, which comes from Central America, is a so-called short-day plant. It needs more than twelve hours of darkness per day over a certain period of time to stimulate the formation of new flowers. This is an adaptation to its natural habitat: In the vicinity of the equator, the days and nights are either slightly longer or shorter than twelve hours, depending on the season; directly on the equator line, they are exactly twelve hours long all year round. There are no distinct climatic seasons near the equator, but there are often rainy and dry seasons. Through the so-called flower induction during the short day phase – the tropical “winter” – the poinsettia is created to form new flower buds, which then open when the climate is most favorable for the fertilization of the flowers.
If the poinsettia only has green leaves instead of colored bracts, it is hardly recognizable at first glance
The poinsettia needs a rest period
If you want to make your poinsettia bloom again, you have to simulate these light conditions over a certain period of time. Before that happens, however, you should first care for your poinsettia so that the red, white, or pink colored bracts keep their color for as long as possible after Christmas. This works best if the location for the poinsettia is as warm and bright as possible and if you water it moderately but regularly with lukewarm water and spray it with rainwater. Under ideal conditions, the bracts remain colored until the end of February. From the end of February to April, the watering of the poinsettia is reduced significantly so that the plant enters a dormant period.
How do you care for the poinsettia from May?
At the end of April, cut the poinsettia back to a height of around 15 to 20 centimeters, depending on the size of the plant, and then slowly increase the watering quantities. Avoid waterlogging at all costs, because poinsettias are very sensitive to this. From May the plant begins to grow stronger again. It is now set up as brightly as possible, but without direct midday sun, and is supplied with liquid flower fertilizer every week until mid-September, which is added with the irrigation water.
As soon as the new flowers appear, the poinsettias also form colored bracts again
New flowers through short exposure
The natural short day in which the new flower buds are formed begins in our latitudes from September 22nd, the beginning of autumn. Now you bring the poinsettia into a bright, warm storage room that is only illuminated by daylight. It is important that you do not open the room door after sunset and that there are no artificial light sources outside that shine into the window, as even the slightest influence of artificial light can disturb the formation of flowers.
An unused room with an external blind that can be closed with a timer is also very suitable. If you do not have a suitable room, you can cover the plants with a large cardboard box or black, opaque film for a good twelve hours a day for eight weeks from mid-September. After around eight weeks of short days, the flower formation is complete and the new colored bracts appear. Now you can bring the poinsettia back into the living room and enjoy the new blossom just in time for the next Christmas.