A typical flower to give at Christmas time, the Christmas star has such lively inflorescences that brighten up the whole house; it is actually an evergreen shrub, which in nature reaches 3-4 meters in height; the flowers are small, gathered in bunches, subtended by enormous colored bracts; the use of the poinsettia as a houseplant has been widespread for some decades, at this time the flower producers were able to produce various hybrids, with very large or curled leaves, with double inflorescences and bracts double bracts , with bracts of various colors, from cream white to bright purple.
The shrub grown in pots remains quite small, and tends not to exceed two meters in height; in the Christmas period in nurseries are mainly rooted cuttings, which do not exceed 25-55 cm in height at the time of purchase, and have a rather slow growth if grown in a container.
Poinsettias are plants belonging to the genus Euphorbia, they are varieties of the Euphorbia pulcherrima species, also called Poinsettia; originally come from Mexico and Central America, now they are also naturalized in some areas of Australia and the Mediterranean area.
The shrub is well branched, although it often tends to empty itself of vegetation in the lower part and to produce a more compact crown in the upper part; the branches are fleshy, only in older specimens do they become woody; the foliage is large, dark green. The inflorescences are naturally produced by the plant in autumn, when the days are short, with a few hours of light.
Growing a Christmas Star
The poinsezie love bright and well-ventilated positions, with minimum temperatures above 10-12 degrees, but with not high maximums, it is therefore advisable to grow these plants at home, in a little heated room, and absolutely far from direct heat sources. These plants love a cool and quite humid climate, so it is advisable to vaporize them often, especially in summer and during periods when the heating or air conditioning system is active. They love luminous positions, but in order to color the bracts that characterize them it is essential that they receive a few hours of daylight; therefore we avoid placing our poinsettia in a room with strong lighting, even occasional lighting due to electric light can delay flowering, and our plant will keep all the green leaves.
This does not mean that these plants should be placed in a shady place, in fact during the natural hours of sunlight it is good to place them in a bright area of the house.
There are those who obviate this problem by covering the plant with a dark paper bag at sunset, to discover it in the morning, during the autumn months.
The poinsezie need regular watering, but it is good to wait for the soil to dry between one watering and another; avoiding leaving the substrate completely soaked with water.
The fertilizations will be regular, every 15 days, for the whole year, using a fertilizer for flowering plants.
Plants and photoperiod
During the year, as we all know, the days have different durations, in July the sun remains high for more than 10 hours a day, while in October we have an insolation of less than 8 hours a day. Plants live thanks to chlorophyll photosynthesis, which takes place thanks to sunlight; for this reason the plants are able to measure the amount of insolation every day, changing their development according to the season in which we find ourselves.
For this reason, when we grow a shrub at home, even if the climate is warm and dry, as if we were in May or June, our plant is aware of the fact that we are in a different season from spring, despite the climate in home seems to declare the opposite.
So the plants grown in the warm at home can go into vegetative rest, although the climate seems favorable for development.
This characteristic of the plants is fundamental for the same to be able to develop at its best; for example many plants, such as spinach, as soon as the days get longer, prepare to produce flowers, because spinach plants would not survive a hot and dry climate, typical of summer.
Poinsettia instead blooms in winter, when the days are short, just before spring; so even if we grow it at home, in the heat, to better imitate the outdoor climate, we will also have to deprive it of light, even artificial light, so that it can produce the typical colored bracts.
But why do we use a Mexican plant as a Christmas gift?
As with many other plants, even at Christmas we use what nature makes available to us, therefore evergreen shrubs of the forest, and conifers, with their green and fragrant needles; in addition to this, in an increasingly globalized world, we also have plants that are flourishing in the rest of the world at this time.
Euphorbia pulcherrima was introduced in cultivation towards the end of the 1800s, for its beautiful bracts; the use of this plant spread slowly, only towards the 1980s it also spread to Europe, when it became easier and less expensive to cultivate this species. The ease of rooting of the cuttings of poinsettia and their red bracts, which recall the colors of Christmas, have quickly made it a very widespread plant at Christmas time, like holly and butcher's broom.
Obviously there are also legends about this, which come directly from Mexico; it seems that at one time a small child went to Christmas mass, eager to bring a gift to Jesus as a child; unfortunately the child was poor and could not afford any gifts, so he took a bundle of twigs from a forest plant; when they arrived in the church, these twigs were filled with enormous inflorescences, typical roses of the Christmas star, as if by miracle, from that day the Christmas stars continued to bloom in the middle of winter, to symbolize that a pure soul is rewarded, and that sometimes for make a gift just think.