The typical Orchid tends t be in a container that is mobile which means tat typically it can be located outdoors in the right time and place to provide nice natural light as well as a good background. i guess if the intent is illustrative-showing the specific structure as opposed to aesthetic you may find some plus in a rather artificial setup,but I'm inclined to favor the what you see is what you get aspect of using natural lighting whenever possible. I tend to prefer a picture of a flower to at least seem to be in a natural setting. A plant that is potted can be moved about. Even if you live in an apartment in a city-somewhere you can get it to a park or other place where you can employ good natural light at a good angle and have a nice background.
Trying to construct a background and the right flash deployment is a good technical exercise but may not be the most effective way to get the best shot. to me,flash is ALWAYS plan B. If there is an option to use natural outdoor light--that tends to be what I do.