Meet the Sunflower
Common names: common sunflower
Scientific name: Helianthus annuus
Family: Asteraceae (aster family)
Genus: Helianthus (sunflower tribe)
There be giants in the land!
When I was growing up in Central Texas, my friends and I would often begin the summer exploring the dense forests of sunflowers that grew in open fields near our homes. To us adventurous and highly imaginative ten and eleven-year old kids, the sunflowers would transform into a variety of interesting and often dangerous creatures.
To the unsuspecting adult these 8-foot giants seemed innocent enough with their huge yellow blooms smiling at the sun, but to us kids who belonged to the secret "Space Rangers" unit knew better. These innocent-looking and lanky spiny creatures were actually aliens from outer space, and the "Space Rangers" were charged with saving the Earth from their spreading invasion.
I must confess that we slew many of these creatures with our “laser swords”, before we were duly informed by “higher parental command" that the sunflowers were not aliens and should be left to live out their normal lives as Texas wildflowers. Today when I see a field of sunflowers (http://www.pbase.com/image/30653488), I smile and remember the many summers of fun we had running through their jungle populations.
The sunflower is a true native of the Americas and has been regarded as a useful plant for over 3,000 years (recent evidence points to an even longer time). Many Native American tribes sought to cultivate the sunflower for a variety of purposes. Over fifteen tribes used various parts of the sunflowers for food, medicine and a source of oil. The seeds were thought to provide an immediate source of energy for war or hunting parties to overcome fatigue. Dyes were extracted from the seed heads of the sunflowers and the blooms were used as decorations.
Early American colonists virtually ignored the benefits of the sunflowers, but the seeds found their way to Russia where the sunflower was botanically enhanced producing the Mammoth Russian sunflower. The enhanced seeds were reintroduced into America in 1883. Presently in the former Soviet Union countries, the seed hulls are also used in the production of ethyl alcohol as a source of fuel.
Today the sunflower is a major horticultural and agricultural product in the USA. Sunflowers are grown for their seeds as food product, as a source of cooking oil, and as a food source for farm animals. The sunflower kernel reportedly is high in vitamin E, Zinc, selenium, folate, iron, vitamin B6 and pantothenic acid.
According to the National Sunflower Association, 90% of the fat in the kernel is monounsaturated and polyunsaturated fat which are the "good fats" containing the beneficial “high density lipoprotein (HDL) cholesterol" which is needed to help carry away the bad cholesterol in the blood.
Does the Sunflower Follow the Sun?
It is a common myth that sunflower heads will follow the sun throughout the day. This is called heliotropism. However, only the immature sunflower buds will exhibit any kind of tropism, since they have leafy green bracts (the back of the flower head) that are exposed. You know from your basic science class that plants will seek out light through a process of phototropism. They do this because they need the light for photosynthesis. Well, sunflower buds will exhibit this due to the exposed green bracts, but the entire plant will also orientate its leaves to get the maximum benefit from the sunlight.
Commercial sunflower fields will seem to march to the tune of the sun in sync, because they are planted uniformly. Mature sunflower heads (which are actually composed of many flowers) will end up generally facing east – because the buds end up back facing the east due to circadian rhythm. Roadside sunflower plants will not be so uniformed, so their mature flower heads might not face uniformly east.
For further geeky study see:
Heliotropism - https://en.wikipedia.org/wiki/Heliotropism (scroll down to the part about the sunflower plant.
Phototropic solar tracking in sunflower plants: an integrative perspective
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4701145/ (The really geeky stuff with the origin of the myth)
Time-lapse video of a sunflower plant
http://plantsinmotion.bio.indiana.edu...solartrack.html - Roger P. Hangarter, Indiana University, Department of Biology
And a sunflower seeding using phototropism
http://plantsinmotion.bio.indiana.edu...m/tropisms.html - Roger P. Hangarter, Indiana University, Department of Biology
Other species of Helianthus in Texas
Other species in Texas include the ashy sunflower (Helianthus mollis), prairie sunflower (Helianthus petiolaris) and the Maximilian sunflower (Helianthus maximiliani). The Maximilian sunflower blooms primarily in August to October providing tall trestle like stalks covered with large yellow blooms. The bloom of the Maximilian is dainty, but very expressive in beauty (http://www.pbase.com/image/21994920). In March of 2016, I came across what at first appeared to be a very early sunflower bloom. After some searching and verification, I discovered it was a Texas sunflower, (Helianthus praecox) – (http://www.pbase.com/image/162829727)
If you have the room in your garden then I highly recommend planting the sunflower, especially the Maximillian species. Seeds can be obtained from Native American Seed (http://www.seedsource.com/catalog/detail.asp?product_id=1028). The sunflower will add beauty to your garden, attract bees and butterflies and provide a good food source for seed-eating birds.
- Iowa lists the wild sunflower, Helianthus annuus as a secondary noxious weed (https://plants.usda.gov/java/noxious?rptType=State&statefips=19), so it might be advisable to consult the ISU Extension Agronomy office in Iowa (https://www.agron.iastate.edu/extension) before planting sunflowers in farm or pasture lands.
- The sunflower is the state flower of Kansas where supposedly you can still find fields of it in bloom in September.
- The florets of the sunflower form a Fermat's spiral (https://en.wikipedia.org/wiki/Fermat%27s_spiral).
Image gallery: http://www.pbase.com/richo/sunflowers
“History of the Amazing Sunflower” - http://www.sunflowernsa.com/all-about/history/
National Sunflower Association: Sunflower Statistics." http://www.sunflowernsa.com/stats/default.asp?contentID=160"
USDA Nutrient Database for Standard Reference - https://ndb.nal.usda.gov/ndb/foods/show/3626?manu=&fgcd
“Helianthus annuus” - https://en.wikipedia.org/wiki/Helianthus_annuus
"Helianthus annuus" - http://www.wildflower.org/plants/result.php?id_plant=HEAN3