Identifying the type of mint. Just to confuse the picture even more, there is a chocolate mint which has purplish stolons. There are, in fact, hundreds of varieties of mint, some of which are commercially grown for oil extraction or for leaf drying, and a lot of which haven't even been given names, being known as Mint 341, etc.
Simply put, watercolor is a painting compound using water-soluble pigments that are either transparent or opaque. Because of the medium itself as well as the paper to which it is applied, watercolor is frequently thought of as a fugitive medium.
What is Pastel? It is dry pigment, the same pigments used in the wet painting media, but without oil, water or acrylic binders. It contains a minimum of binder and is basically pure pigment. Historic dry pastels should not be confused with oil pastels. Dry pastel is no more like oil pastel than watercolor is like oil paint.