Temporary text: cited from https://www.growveg.com/guides/the-fun-of-growing-sunflowers/
When the first Europeans arrived in America, they were surprised and delighted to see sunflowers growing near settlements everywhere they went. Some were perennial species of Helianthus, while others were the same annual species I grow in my garden. Actually, the sunflowers grow themselves. All I do is provide them with space.
Plant historians think sunflowers have been domesticating themselves by pleasing gardeners for more than 4,000 years. Annual sunflowers quickly make themselves at home in disturbed soil, and because of their fast growth rate and impressive height, they can often rise above competing weeds. They are also natural self-sowers. As the seed heads mature, seeds break off a few at a time and fall to the ground. Others are dropped in unexpected places by birds, which consider sunflowers seeds a great delicacy.
Upright or Branching?
Like many plants native to America, sunflowers did a bit of traveling before plant breeders discovered them and made them better. In the case of sunflowers, it was Russian botanists who took up the cause after discovering that oil pressed from the seeds could be consumed during Lent, when butter and lard were forbidden by the Russian Orthodox Church. Today, sunflower oil is an essential ingredient in potato chips and other snack foods. In the kitchen, it can make a nice change of pace from olive oil.