Buttonbush is a common shrub of many wetland habitats in its range, including swamps, floodplains, mangrove, pocosin, riparian zones, and moist forest understory. It is a member of the flora in the Everglades. (Wikipedia)
C. occidentalis has a number of historical medicinal uses, but it is also toxic due to the presence of cephalathin(Cephalathin will induce vomiting, paralysis, and convulsions if ingested.) The seeds are a food source for some waterfowl. "Common buttonbush is used for erosion control along shorelines. It forms dense stands and its swollen plant base stabilizes the plant." (http://plants.usda.gov/plantguide/pdf/pg...) This bush is located on the shore of Old Hickory Lake.