The flavour and aroma of herbs is provided by the essential oils that are found in the leaves, flowers, bark, roots or seeds of the plant. Essential oils are complex mixtures of aromatic substances that give the unique characteristic of each herb and are found in
special cells in the plant called trichomes. Almost all herbs can be grown for the production of essential oils but the yield of oil from each species dictates whether this is commercially viable.
England has historically been most famous for the production of lavender and peppermint oils and in the southeast of England both oils have been grown commercially since the 18th Century.
