Sneezeweed is one of the latest bloomers, opening their yellow flowers in late-August through October. 
 
This cheerful plant, with its big heads and petals flaring out like hula skirts,  is host to caterpillars of the Dainty Sulphur and Blackberry Looper.  It also attracts butterflies, beetles, native bees.
 
The leaves were once used to make a snuff that caused sneezing, intended to rid the body of evil spirits.
 
Helen's Flower does best in full sun; in part shade it may rely on its neighbors for support.
 
Fun fact: The genus name, Helenium, refers to Helen of Troy. Legend has it that the flowers sprang from the ground where Helen's tears fell. (U.S. Forest Service)
Native range and additional photos and information here