I love them. I don't usually have to plant them. I get olunteers from the bird seed from the previous winter.
There's a house near me that has a sunflower with a HUGE bloom - like the mammoth. However, the plant itself only about 3' tall.
I have no idea what variety it is.
Did a liitle searching - I think it might be Helianthus annuus "Little Dorrit ".
Hmmmmm.. maybe next year.