Poinsetia on Christmas and beyond
Poinsetia is also known as “star of Bethlehem” and its scientific name is Euphorbia pulcherrima (euphorbia the super-elegant). It is indigenous to Mexico, where Aztecs used it to produce red dye and as an antipyretic medication. However, it was ascribed with toxic and allergic actions.
In many countries, Greece included, poinsettia is the most popular Christmas plant, while in Spain it is known as “Easter flower”. The appealing part of the plant is the red-colored rosette (crown) of leaves, called bracts, placed under its small and yellow flowers. There are also varieties with bracts colored white, pale yellow, orange, pink or bicolor pink and white.
Poinsettia is a shrub or tree of moderate growth with a height of 0.6-4 m. As a tropical species, it does not withstand low temperatures, thus grows as a houseplant in our country. It also grows outdoors, in areas with temperatures higher than 2°C, in places protected from direct sunlight and wind.
This plant has an intriguing point. The desirable red bracts appear when flowers are formed. Blooming is triggered when the plant is subjected to long-night/short-day conditions along the diurnal period. Thus, it is a short-day species. In particular, it demands the alteration 14 h full darkness/10 h light for more than five consecutive days. Since the transition in these conditions is gradual, it lasts for at least two months. Specifically, to synchronize flowering to Christmas, a gradual reduction in light exposure should begin from October to November. In nurseries black cloth plant covering is adapted to increase the length of the dark period. At the same time, lighting enhancement (using artificial light) during the light period is applied to pronounce plant color hue and contrast (red and green). Without photoperiod manipulation, plant blooming will belated. This could be the reason why it is known as “Easter flower” in Spain.
Poinsettia is a perennial plant. Leaves are wilted, after bloom completion, but the plant is still active, being in a latent condition. Thus it can be preserved till the next winter, providing limited care, regarding the crown shaping to maintain good appearance.
In April, after leaf wilting, pruning is applied to promote plant re-growth, leaving 2-3 buds in each shoot. Mind the white milky fluid from sections, because it is irritating to the skin. The plant needs are limited while vegetation is poor. Watering once every 15-20 days is enough. Temperature increase will cause buds to burst and foliage to form. Watering should then increase gradually and a liquid fertilizer (composite) every 15-20 days should be provided. On hot summer days, plant may need to be watered every day. When first leaves appear poinsettia could be transplanted, if necessary, in a larger pot. Handle it with care and avoid destroying the root-ball. Ample watering is needed immediately after re-potting.
Poinsettia should be placed in a fully sun-lit place (not direct sunlight) far away from heating and cooling sources. It will then form a dense and bright foliage, which will last till the next bloom completion.
The beauty of your own crafted poinsettia will reward your efforts.