Mints are plants of the genus Mentha. Some might class peppermint and spearmint as too vigorous to be used in some situations. However, these plants will survive in horrible boggy clay that might not support much of anything else, and over time they will raise the level of the soil and add significant biomass. Plants that will till hardpan have great value in bioremediation of crushed and dispirited earth. These plants also make excellent compost. They also improve habitat for worms.