Mint herbs are fast-growing and can be easily established in the gardens; therefore established plants need little care. They have a tendency to form colonies through vast networking of runners (creeping stems) along the soil surface and may become invasive if their growth is unchecked. Mint herbs are mainly grown for its aromatic foliage which is used as a culinary herb. Both fresh and dried leaves are used for culinary purposes. Mint is grown as an annual leafy vegetable if they are grown for culinary purposes. For commercial purposes such as for oil extraction, mint is grown as a perennial herb. Some varieties of mint such as peppermint, spearmint and Japanese mint are mainly grown for extracting mint oil. A mint herb plantation is having an economic life of more than three years.