I had sent some Bott's Strain seeds to Bernard Lavery. He grew them in 8 inch pots along the side of the house. Very impressive to have a sunflower this size grown, and only grown in a 8 inch planter. One of the sunflowers grew to over 17 ft. tall. Generally, Bott's Strain are single headed, but he has a few that are multi-headed. I've seen this a few times myself with my own plants.