To cast down your bucket where you are means that you don't need to travel far in order to find what you are looking for - there are many valuable resources exactly where you are. What Washington is trying to say here is that he wants both black and white people to work together and rebuild the South in order to make it prosperous and forget about their differences.
You could use the adjective, gaudy, to describe a noun. The noun, quail, could be used as the sentence subject (either direct or indirect). For example: "The gaudy pheasant made the dull quail ashamed of its plain feathers."
