Analysis: the flower symbol of Ukraine, sunflowers are also an essential crop which make us smile and improve the environment
By Zoë A. Popper and Karen L. Bacon, NUI Galway
Planting sunflowers across Ireland is a vibrant display of solidarity and support for Ukraine and its people. Most of us are aware that the sunflower is the flower symbol of Ukraine, but probably have not thought about why this is the case and how appropriate this choice is, particularly now.
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From NBC News, how sunflowers have become a symbol of support for Ukrainians
You are probably familiar with sunflowers. Maybe you grew them as a child (or even as an adult) and measured their height against yours? Maybe you admire Vincent Van Gogh's sunflower paintings, painted in three shades of yellow during his time in Arles in the South of France, in an effort to communicate gratitude. Or maybe they remind you of summer holidays with fields of yellow sunflowers with their heads all facing in the same direction. This feature, is known as heliotropism, and gives them the name tournesol in French, as their flower heads turn to follow the sun helping them to attract pollinators.
Sunflowers have an enormous number of relatives. They belong to one of the largest groups of flowers, the Asteraceae, or daisy family, first described as Compositae in 1740 by the Dutch botanist Adriaan Van Royan. There are over 32,000 species of Asteraceae and many members such as Echinacea purpurea (purple coneflower), arnica and feverfew are used medicinally, while others such as dahlias and chrysanthemum (whether you like them or not) are widely grown for their horticultural and aesthetic value.
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From RTÉ News, a Ukrainian family in Carlow are selling sunflower seeds to raise money for the Red Cross
With initiatives such as NoMowMay, we are increasingly aware of the value of our native species, and many of them are relatives of the sunflower, including dandelions. However, what makes these species so valuable to pollinators is a particular feature that is possessed by most of the Asteraceae.
It is what most of us think of as a single flower but is actually many flowers grouped together in a structure that is known botanically as a "capitulum". The star-like capitulum are made up of many smaller central disc flowers, surrounded by ray flowers organised to look like a larger flower. This arrangement means that a pollinator, such as a bee, is able to gather pollen and nectar from many flowers in one visit. The flowers of members of the Compositae can therefore be thought of as a community that supports the survival of the species.
Several Asteraceae are edible, including chicory (sometimes used as a coffee substitute on account of its bitter taste), lettuces and Jerusalem artichokes, but sunflowers are the most important member of this botanical group that are grown as a crop. Although the sunflowers originated in North America where they have been cultivated for over 4,500 years and they were introduced to Europe in the 17th century. They provide pigments and oils for cosmetic applications and the stalks have been used in construction.
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From Epic Gardening, how to grow sunflowers successfully at home
We are probably more familiar with their seeds, which are high in oil and can be eaten, often roasted, as a tasty snack. The majority of sunflower seeds are used to extract the sunflower oil used for cooking and is thought to be the best oil to make chips. Sunflowers are grown in many European countries today, but it's Ukraine, where they were introduced in the 18th century by the Spanish, which now provides over 50% of the sunflower oil exported worldwide.
Sunflowers come in enormous variety of both colour (from dark reds and oranges, through yellows, to pale cream), and sizes (from 'Big Smile’ at about 30cm in height to ‘American Giant’ which can get up to 4 metres). The tallest sunflower ever grown was in Germany and reached a height of 9.17 metres!
Whilst you may not be aiming to grow sunflowers as tall as that, it is recommended that sunflower seeds are sown from mid-April to the end of May. Although they prefer well-drained soil and full sun, they are highly resilient and have the ability to take up and accumulate high levels of toxic materials in their root systems. For this reason, they have been used in phytoremediation efforts to reduce the level of certain metals, and radiation in soils and water, including after the explosion at the Chernobyl power plant in 1986. Sunflowers are an essential crop which make us smile and improve the environment.
Fascination of Plants Day takes place at NUI Galway on Wednesday May 18th
Dr Zoë A. Popper is a lecturer and researcher in Botany and Plant Science at the School of Natural Sciences at NUI Galway. Dr Karen L. Bacon is a Lecturer in Plant Ecology, Botany and Plant Sciences at the School of Natural Sciences at NUI Galway
The views expressed here are those of the author and do not represent or reflect the views of RTÉ
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