Buttonbush, a native species, has been added to the USWildflowers database (08/19/2012.) Scientific name is Cephalanthus occidentalis.  Photo below was taken in Hamilton County, TN on Aug 19, 2012. Go to the Buttonbush detail page for more photos and information.

Buttonbush, Common Buttonbush, Button Ball, Riverbush, Honey-bells, Button Willow – Cephalanthus occidentalis