How about Cleome? They get quite wide as well as tall.

Cosmos are great! Mine get 5 to 6 feet tall and I sometimes have to stake them up. They will branch out and get fairly bushy if you pinch them. Donna

There are now many kinds of sunflowers in several colors, heights, and flower forms.

MM

AGree with recommendation for cleome. Also, I'm a big fan of Tithonia (Mexican sunflower). Even here in Nebraska, they get a good five feet tall by summer's end.

dan

Even though I'm years late to this conversation, because this is the first result to come up on Google search for "fast growing tall annual", let me suggest the castor plant and some okra plants. They get to be 7ft+ tall within a year.

Hi Yanggers,

I wrote the original question and found it again just now when looking to see what people are growing. Your comment brought it up close to the top. I will look into your suggestions as I often need a tall plant.

Ginny

zinnias are great, strongly recommend them