Italy is a major producer of sunflowers which are grown primarily for their seeds and oil. July in Umbria and Tuscany brings fields full of the glorious yellow flowers which Italian artist, Pablo Picasso, immortalized in his famous painting.
Helianthus, or sunflowers, is a genus of plants comprising about 70 species in the family Asteraceae. The genus is one of many in the Asteraceae that are known as sunflowers.
The tallest sunflower variety, American Giant can grow to up to 16 feet tall, with stronger stalks than other tall types, and enormousleaves. Plants are topped by 10 inch golden sunflowers.
A native of the Americas, the sunflower symbolized the image of the Sun God to the Incas and its sunny presence and edible seeds have linked the plant to humans for 4,000 years or more. In fact, the first known signs of the sunflower’s domestication by humans was in around 2,300 B.C in Tennessee at the famous Hayes site.
The sunflower’s seeds have been long prized for their oil content and are sold from China and the U.S to Russia as a snack food; it has also been cultivated across Italy for centuries because of these qualities. Research is currently being carried out to refine the oil for use as a bio-diesel.
The composition of the sunflower’s florets itself is also rather fascinating and has been studied by mathematicians like Leonardo Fibonacci (a 13th Century Italian mathematician from Pisa, Tuscany) and Greek mathematicians alike.
In simple terms this means that there can be 34 spirals in one direction and 55 in the other direction, or on some larger flowers can range from 89 to 144. The symmetry and logic of a sunflower’s flower structure has astounded and fascinated artists and mathematicians alike and manages to cross many fields of science in one simple… flower.
The sunflower’s complex mathematical structure is based upon the famous “Golden ratio” (again, discovered by Fibonacci) where the growth rate of successive numbers gives a ratio which converges on1/2x (1+/5) = 1.618, known as the “Divine proportion” or “Golden section” of geometry and aesthetics in nature.
There are even curiosities concerning the sunflower’s cultivation, as the young seedling of the sunflower soon sets about establishing the position of the rising sun in the east, on its emergence from the soil and faces in that direction throughout its life. This ability to grow in the direction of the sun is known as Heliotropism and has earned the flower the name of “Girasole” (Sunturner) in Italy.
Leaving science aside, the sunflower’s cultivation needs are really quite simple; full sun, fertile soil and good watering after planting. By addressing these simple requirements the sunflower will happily provide us with a flower spectacle that is rivaled by few others and its presence will bring sunshine to any vegetable garden or plain flower border.