Those are pretty! My grandma grows them every summer, they are HUGE!!!!! I am growing some.... but they look PATHETIC! I water & fertilize them... I gave some of the same seeds to my grandma and hers look pitiful too. They were Mammoth & Grey Stripe. On the other hand, the rest of my garden is doing wonderful! (First year gardening) I LOVE SUMMER!
edit-mine are about chest high, if even, and no thicker than a pencil, and they look like they are about to bloom, I already see yellow petals! I am almost at the point of digging them up, since I have to drag the hose all the way to the front yard just to water 'charlie brown' sunflowers, lol, but out of sheer curiosity I think they will stay.