I grew this monster sunflower a few years back....HUGE flower head diameter! I planted quite a few today, and will have fun cross-pollinating them with those lovely various ornamental sunflowers to see if I can breed giant ornamentals. MUCH less waiting to see results when I bred roses...sometimes I have to wait 1-3 years to see my first bloom. In the case of my hybrid Alba 'Brenda Mowery' I had to wait seven years to see my first bloom!

http://store.underwoodgardens.com/Skyscraper-Sunflower-Helianthus-annuus/productinfo/F1122/