After Christmas, the poinsettias usually leave the apartment. But this is not necessary, because, with the right care over the summer, Christmas stars can bloom more often.
The poinsettia ( Euphorbia pulcherrima ) usually only lines the window sills at home during Advent – afterward, it goes to the garbage. Because what many do not seem to know: The poinsettia is a perennial milkweed plant ( Euphorbiaceae ). Even in our latitudes, the colorful Christmas messenger can easily live for several years. However, to ensure that it always blooms on time for Christmas, you have to take good care of it in summer. We give tips on care and show you how to get your poinsettia to bloom again.
Maintain poinsettia in summer
If the colorful poinsettia is to shine again in the following winter, it must first be brought successfully over the summer. After flowering, it can initially move out of sight to a slightly cooler and darker place. The water supply can also be reduced. In mid-May, when there is no more risk of frost, you can either plant the poinsettia outside or put it outside in a pot. Before this step, it is advisable to cut back the withered shoots and repot them in a fresh substrate and a slightly larger pot.
With the sprouting of new shoots after the pruning, fertilization should then be resumed and the water requirement should also increase from now on. It is ideal to provide the poinsettia with nutrients in many small gifts. A complete fertilizer such as our Plantura organic universal fertilizer, which can be administered once to two weeks with the watering, is ideal for this. The growth of the poinsettia will not stay as nice and compact as with freshly bought specimens from a professional gardener.
They use special growth regulators to regulate the length growth of the shoots and thus ensure a compact shape. However, you can counteract extreme growth in length by watering sparingly. The moderate and non-hazardous drought stresses the growth of the poinsettia. Nevertheless, there remains a fine line between useful drought stress and lasting drought damage.
Caring for poinsettias after flowering and in summer:
- Place in a slightly cooler and darker place after flowering; Reduce pouring
- April: Cut back the dead shoots and repot in fresh substrate
- Mid-May: Poinsettia can move outside (pot or bed)
- Regular fertilization (once or twice a week) with a complete fertilizer during the main growing season (May-August)
- TIP: After pruning, the fresh shoots can also be used to propagate poinsettias from cuttings
How is the poinsettia made to bloom again?
To make your Christmas star bloom again, the blooming behavior of the milkweed family must be known. The formation of the colored bracts and the actual flowers can be specifically controlled via the length of the day. The poinsettia is a so-called short-day plant. From a specific, critical day length of fewer than twelve hours, the poinsettia switches on the flower formation, so to speak. Depending on how short the day is, it takes another eight to twelve weeks until the colored bracts of the poinsettia are fully developed. The shorter the day, the faster the colored bracts form.
So that the star shows its best side in time for Christmas, it must be ensured by the beginning of October that the “day” lasts longer than twelve hours. This can be achieved with a so-called stray light – which a normal light bulb is enough for. From the beginning of October, it is then necessary to expose the plant to light for a maximum of twelve hours a day. Then the poinsettia must be darkened.
If it is on the windowsill, you can, for example, put a cardboard box over it. In a greenhouse, things get more complex: You can attach a black film here, but it has to be removed every morning and completely re-attached every evening. Light shining through even in small places (for example from a street lamp) can disrupt and even prevent the poinsettia blooming induced by the “short day”. It is easier to simply adjust to the natural length of the day, even then the poinsettia will bloom. However, it must also be meticulously protected from stray light.
To make the poinsettia bloom (again):
- The poinsettia is a short-day plant with a critical day length of 12 hours
- Day lengths of less than 12 hours induce the formation of the flowers
- Depending on the length of the day, it takes 8 to 12 weeks from the first short day to flowering – the shorter the short day, the faster the flowering usually comes
- In the short-day phase, the poinsettia must be protected from any other disruptive light sources and placed in a dark place