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.
Your brush with destiny. Watercolor brushes are traditionally made of the red sable hair that comes from the pricey little critters of fur coat fame. Over the centuries artists have winnowed out the best materials for their tools.