Indian tobacco (Lobelia inflata) is an annual native plant in North America (eastern and central regions). It blooms starting in mid-summer and continues blooming until the first hard frost in the fall. Flowers are quite small so it takes a close look to see their wonderful design.
Leaves have distinct margins. They are finely toothed with a bit of waviness. They also have white dots scattered along the margin.
Watch this video about Indian tobacco (Lobelia inflata) to see close-up views of the small flowers, the white dots on the leaves, and the tiny brown seeds.