this plant grows to 6-8ft tall and taller, resembles mimosa, single stem, I believe small yellow flower, 1-1.5″ seed pods, opposite leafs , annual, dies at frost, appears mid summer and grows fast to 8ft. seems to prefer moist low soils. I see it every where from lake Moultrie, to south of Summerville sc. I live just south of Cross, SC Randy
your plant is called coffeeweed, scientific name Sesbania herbacea, formerly called Sesbania exaltata. It is a native that sometimes appears weedy in wet areas and croplands. It is a type of bean, but not edible as far as I know. I’m not sure why it is called coffeeweed, because it can be toxic to people and livestock. A nice looking plant, though.
Steve Hill, Botanist, SCNPS