Japanese millet is a quick growing grass that provides excellent habitat for waterfowl and other wildlife.  It tolerates wet ground and even standing water as long as the plant is above it.  Japanese millet is primarily seeded in wetland areas when they are drier in the summer then grows quickly before they get wet in the fall.  Around larger wetland areas, it can be flown on and the seed will float into the coast line and be seeded that way.  Buckwheat would be a good companion.  The white in the middle pictures are from buckwheat flowers.