I was sick this year and my garden went wild from lack of attention, but I did notice the odd sunflower coming up here and there and I let them be, enjoyed them when they bloomed and saved the heads for the birds. But, in corner above the one waterfall there were two that just kept growing and there were no heads. They grew and grew and grew AND, oh my, one is around 14 feet an the other around 12. My neighbour used my phone to take a picture from outside our fence.