I have iron window boxes hanging on the fence between the house/patio and the driveway. Two are in sun and planted alike. This is one of them: now that the petunias are draping over the front and back, they're looking the way I envisioned them back in May.
This is rudbeckia "Herbstonne" - it has a wonderful bright yellow flower, and the plant is over 6 feet tall. Yarrow - I used to have a lot of this, but then it kind of disappeared for a few years, and is now coming back. I love when plants do that! (well, not the disappearing part so much!)