I'm growing two different varrieties of sunflowers this season. One I got from some leftists at a community event, I can't remember the variety but I planted them in a raised bed and they have grown very tall with one starting to bloom the first week of July. I affectionatley call these "The People's Sunflowers" since I cannot remember the variety. The other sunflower variety I am growing are Mammoth sunflowers that we got at a supermarket chain and a local nursery respectively.
Sunflowers have a lot of really fascinating effects on the soil around them. Apparently they pop up in other crop fields and (esp. in the midwest) are considered a weed. Sunflowers have also been used to filter harmful metals and chemicals from soil and water. Sunflowers specifically have shown the capacity to drastically reduce uraniam concentrations in water at an experiment near Chernobyl. The wiki page also mentions they can be used to filter radionuclides, aresnic, and with the right assistance lead.
It should be noted that sunflowers used to extract radionuclides from water did not metabolize or eliminate the radionuclides. The flowers themselves absorb and hold on to the radionuclides and were disposed by the research team as radioactive waste. Disposal aside, however, these seem like very important plants in the arsenal of any urban farmer, especially in industrial areas.
Currently The People's sunflowers are much further along and developed than the mamoth variety. This is certainly affected significantly by the location and quality of soil. The People's sunflowers were planted in a raised bed that had been overgrown and only recently weeded. This area recieves full sun and seeds were sown directly in the soil.
In contrast the Mammoth seeds were planted in a side bed with rockier more compacted soil. They also spend much longer in the shade each day. I also initially started The Mammoths in seed starting pots that were not designed to break away. (I learned later that sunflowers, like carrots have a single main taproot that grows directly down. The risk of damage to this root is high enough and can effect the plant enough that they generally do much better when planted directly in the soil after the last frost date)
Several plants we are trying currently have struggled through the first heat wave, and with the hottest weeks of the summer still ahead of us it's been nice to see the extra inches of shade the tallest sunflowers have been giving the rest of the plants in that bed. I will be much more aware of the shading potential that sunflowers can create in the future.
Some of the research I've done into using the stalk of sunflowers so far has recomended planting beans or other vining plants. One gardener recomended planting a bean plant at the base of the stock after you have harvested the flower head. (You would cut the flower off of the stalk at the top instead of uprooting the plant immediatley.
So far culinary uses for the plant that we're thinking about trying include; steaming sunflower buds as you would artichoke hearts, roasting the head of the sunflower as it starts to develop seeds (but before the shells harden), and salting and roasting (like the sunflower seeds in gas stations). From the limited research I've done sunflowers are clearly used in indigenous cooking and am hoping to do more research on that. I am reading "Egress: On Mourning, Melancholy, and Mark Fisher" by Matt Colquohoun.
Photos Coming Soon!