I can’t figure out why this is called “shrubby” primrose willow, since it is not shrubby in the slightest. Nonetheless, it is located in marshes, wet flatwoods, and pond margins from the northern and central peninsula west to the central panhandle and Collier county. It blooms from spring to fall. There are nearly 30 species of Ludwigia in Florida (Wunderlin, 2003).
Shrubby primrose willow can be found in NC, SC, GA, AL, and FL (Kartesz, 1999).
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.