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.
Watercolor paper differs from manufacturer to manufacturer, so experiment not only with the different kinds of paper but also with various brands of paper. Watercolor paper is usually white, but it need not be. A variety of cool and warm tints is available. Use acid-free paper for paintings you wish to keep as this will yellow less with age.