Look at these two. Aren't they suppose to be stuffing the pollen in sacks? Looks like they are trying to wear it..;)
Here's more info if you're interested.
However, for commercial farmers growing commodity crops, the sunflower, like any other unwanted plant, is often considered a weed. Especially in the midwestern US, wild (perennial) species are often found in corn and soybean fields and can have a negative impact on yields.
Sunflowers can be used in phytoremediation to extract toxic ingredients from soil, such as lead, arsenic and uranium. They were used to remove cesium-137 and strontium-90 from a nearby pond after the Chernobyl disaster, and a similar campaign was mounted in response to the Fukushima Daiichi nuclear disaster.The evidence thus far is that the sunflower was first domesticated in Mesoamerica, present day Mexico, by at least 2600 BC.Many indigenous American peoples used the sunflower as the symbol of their solar deity, including the Aztecs and the Otomi of Mexico and the Incas in South America. Francisco Pizarro was the first European to encounter the sunflower in Tahuantinsuyo,Peru. Gold images of the flower, as well as seeds, were taken back to Spain early in the 16th century.