Cosmos Bipinnatus

Cosmos bipinnatus, commonly called the garden cosmos or Mexican aster, is a medium sized flowering herbaceous plant sometimes grown in gardens. It can be found in the wild in much of North America where it is a garden escapee, sometimes becoming weedy.
This species is considered a half-hardy annual, although plants may re-appear via self-sowing for several years. The plant height varies from two to four feet. The cultivated varieties appear in shades of pink and purple as well as white. Its foliage is finely-cut into threadlike segments.

Some more info on Wikipedia

Photography: jtyc