Sunflowers are ~7' tall! (some are shorter) Flower heads starting to form but not yet open

Wow, the most vigorous sunflowers are about 7' tall!  All the tall ones are in the backyard.  The front ones are still fairly short, maybe 4 or 5 feet tall.  There is a shortie in the backyard too, one of the ones that lived in a tiny "pot" for a long long time.