An herb is an aromatic plant that is used by people most commonly in cooking, but sometimes for medicinal purposes, as an insect repellant, as a source of dye, and sometimes for their attractive aesthetics. Herbs are not necessarily plants that are taxonomically related to each other—what these plants share is a usefulness to humans, not an evolutionary lineage.
In general, herbs are non-woody plants that are grown from seed, and they can be annual, biennial, or perennial species. Plants that grow from bulbs, such as the species of crocus (Crocus sativus) that saffron is derived from, are not considered to be herbs. Nor are aromatic woody plants, such as the sweet bay (Laurus nobilis) or common pepper (Piper nigrum), which are considered to be spices.
There is a wide variety of herbs that are commonly cultivated. A few of the ones that are frequently used as foods are briefly described below.
The parsley (Petroselinum hortense) is a biennial plant in the carrot family (Umbelliferae or Apiaceae). The original range of this species was the Mediterranean region, from Spain to Greece. This aromatic plant is commonly used to flavor cooked meals, and as an attractive garnish of other foods. A variety known as the turnip-parsley (P. h. tuberosum) is cultivated for its thick, aromatic root, which is used in soups and stews.
Dill (Anethum graveolus) is another member of the carrot family, also native to the Mediterranean region. It is an annual plant, and is used to flavor a wide range of cooked dishes, as well as pickled cucumbers and other vegetables.
Caraway (Carum carvi) is a biennial umbellifer. The seeds of caraway are mostly used to flavor cheeses and breads, and also a liqueur known as kummel. The seeds of anise or aniseed (Pimpinella anisum) are used to flavor foods, to manufacture candies, and a liqueur known as anisette.
A number of herbs are derived from species in the mint family (Menthaceae). The common mint (Mentha arvensis), spearmint (M. spicata), and peppermint (M. piperita) are used to flavor candies, chewing gum, and toothpaste, and are sometimes prepared as condiments to serve with meats and other foods. Sweet marjoram (Origanum majorana) is used to flavor some cooked meats and stews. Common sage (Salvia officinalis) is used to flavor cooked foods, and in toothpaste and mouthwash.
Other herbs are derived from plants in the mustard family (Brassicaceae). The seeds of mustard (Brassica alba), garden cress (Lepidium sativum), and white mustard (Sinapis alba) are ground with vinegar to produce spicy condiments known as table mustard. The root of horse radish (Cochlearia armoracea) is also ground with vinegar to produce a sharp-tasting condiment, often served with cooked meats.
Although they may be nutritious in their own right, most herbs are too strong tasting to be eaten in large quantities. However, these plants provide a very useful service by enhancing the flavor of other foods. Many people are great fans of the use of herbs, and they may grow a diversity of these plants in their own herb gardens, to ensure a fresh supply of these flavorful and aromatic plants.