Oregano (pronounced UK: /ɒrɨˈɡɑːnoʊ/, US: /əˈrɛɡənoʊ/) – scientifically named Origanum vulgare by Carolus Linnaeus – is a common species of Origanum, a genus of the mint family (Lamiaceae). It is native to warm-temperate western and southwestern Eurasia and the Mediterranean region.
Oregano is a perennial herb, growing from 20–80 cm tall, with opposite leaves 1–4 cm long. Oregano will grow in a pH range between 6.0 (mildly acid) and 9.0 (strongly alkaline) with a preferred range between 6.0 and 8.0. The flowers are purple, 3–4 mm long, produced in erect spikes. It is sometimes called Wild Marjoram, and its close relative O. majorana is then known as "Sweet Marjoram".
Description of Plant Biology
Closely related to the herb marjoram, Oregano is also known as wild marjoram. Oregano is a perennial, although they are grown as annuals in colder climates as they often do not survive the winter months.
Main constituents include carvacrol, thymol, limonene, pinene, ocimene, and caryophyllene. The leaves and flowering stems are strongly antiseptic, antispasmodic, carminative, cholagogue, diaphoretic, emmenagogue, expectorant, stimulant, stomachic and mildly tonic.
Many subspecies and strains of oregano have been developed by humans over centuries for their unique flavors or other characteristics. Tastes range from spicy or astringent to more complicated and sweet. Simple Oregano sold in garden stores as "Origanum vulgare" may have a bland taste and larger, less dense leaves, and is not considered the best for culinary uses, with a taste less remarkable and pungent. It can pollinate other more sophisticated strains, but the offspring are rarely better in quality.
Syrian Oregano (Origanum vulgare syriacum)
Notable subspecies are:
- Origanum vulgare gracile (= O. tyttanthum). Originally from Khirgizstan. It has glossy green leaves and pink flowers. It grows well in pots or containers, and is more often grown for added ornamental value than other oregano. Pungent and spicy.
- Origanum vulgare hirtum – Italian Oregano, Greek Oregano. A common source of cultivars with different aroma than those of O. v. gracile. Vigorous and very hardy. It has darker green, slightly hairy foliage. Generally considered the best all-purpose culinary subspecies.
- Origanum vulgare onites – Cretan Oregano, Turkish Oregano, rigani, "pot marjoram". A tender perennial growing to 18 inches tall, with pale green to gray-green woolly rounded foliage. Strong, intensely spicy flavor.
- Origanum vulgare syriacum – Syrian Oregano, Lebanese Oregano, za'atar – Larger leaves that vary in colors ranging from pale green to grayish. Their taste is pungent and similar to Greek Oregano.
Example cultivars are:
- 'Aureum' – Golden foliage (greener if grown in shade). Mild taste.
- 'Greek', 'Kaliteri' – O. v. hirtum strains/landraces. Small, hardy, dark, compact, thick, silvery-haired leaves, usually with purple undersides. Excellent repuration for flavor and pungency as well as medicinal uses. Strong, archetypal oregano flavor (Greek kaliteri: "the best").
- 'Hot & Spicy' – O. v. hirtum strain.
- 'Nana' – dwarf cultivar.
Cultivars traded as 'Italian', 'Sicilian' etc. are usually Hardy Sweet Marjoram (O. ×majoricum), a hybrid between the southern Adriatic O. v. hirtum and Sweet Majoram (O. majorana). They have a reputation for sweet and spicy tones, with little bitterness, and are prized for their flavor and compatibility with various recipes and sauces.
Dried oregano for culinary use.
Oregano growing in a field.
Oregano is an important culinary herb. It is particularly widely used in Turkish, Palestinian, Syrian, Greek, Portuguese, Spanish, Latin American, and Italian cuisine. It is the leaves that are used in cooking, and the dried herb is often more flavourful than the fresh.
Oregano is often used in tomato sauces, fried vegetables, and grilled meat. Together with basil, it contributes much to the distinctive character of many Italian dishes.
It is commonly used by local chefs in southern Philippines when boiling carabao or cow meat to eliminate the odor of the meat, and to add a pleasant, spicy flavor.
Oregano combines nicely with pickled olives, capers, and lovage leaves. Unlike most Italian herbs, oregano works with spicy foods, which are popular in southern Italy.
Oregano is a widely used ingredient in Greek cuisine. Oregano adds flavor to Greek salad and is usually added to the lemon-olive oil sauce that accompanies many fish or meat barbecues and some casseroles.
In Turkish Cuisine, oregano is mostly used for flavoring meat, especially for mutton and lamb. In barbecue and kebab restaurants, it can be usually found on table, together with paprika, salt and pepper.
Oregano growing in a pot.
It has an aromatic, warm and slightly bitter taste and can vary in intensity. Good quality oregano may be strong enough that it almost numbs the tongue, but the cultivars adapted to colder climates have often unsatisfactory flavor. Factors such as climate, seasons and soil composition may effect the aromatic oils present, and this effect may be greater than the differences between the various species of plants.
The related species Origanum onites (Greece, Turkey) and O. heracleoticum (Italy, Balkan peninsula, West Asia) have similar flavors. A closely related plant is marjoram from Turkey, which, however, differs significantly in taste, because phenolic compounds are missing from its essential oil. Some varieties show a flavor intermediate between oregano and marjoram.
The dish most commonly associated with oregano is pizza. Its variations have probably been eaten in Southern Italy for centuries. Oregano became popular in the US when returning WW2 soldiers brought back with them a taste for the “pizza herb”.
Hippocrates used oregano as an antiseptic as well as a cure for stomach and respiratory ailments. A Cretan oregano (O. dictamnus) is still used today in Greece as a palliative for sore throat.
Oregano is high in antioxidant activity, due to a high content of phenolic acids and flavonoids. It also has shown antimicrobial activity against strains of the food-borne pathogen Listeria monocytogenes.
In 2005, the US Federal Trade Commission brought legal action against a firm that had claimed that oil of oregano treated colds and flus and that oil of oregano taken orally treated and relieved bacterial and viral infections and their symptoms, saying that the representations were false or were not substantiated at the time the representations were made, and that they were therefore a deceptive practice and false advertisements. The final stipulation on the matter said that no representation as to any health benefit could be made without "…competent and reliable scientific evidence…"
Other plants called "oregano"
- Cuban Oregano (Plectranthus amboinicus, formerly Coleus aromaticus), also of the mint family (Lamiaceae). Sometimes also called "Mexican oregano", it has large and somewhat succulent leaves.
- Mexican Oregano (Lippia graveolens) is not of the mint, but of the closely related vervain family (Verbenaceae), including e.g. the Lemon Verbena (Aloysia citrodora). It is a highly studied herb that is said to be of some medical use and is common in curandera (female shamanic practices) in Mexico and the Southwestern United States. Mexican oregano has a very similar flavour to oregano, but is usually stronger. It is becoming more commonly sold outside of Mexico, especially in the United States. It is sometimes used as a substitute for epazote leaves; this substitution would not work the other way round.
- Poliomintha longiflora is also occasionally called "orégano" in Latin America.
Oregano is the anglicised form of the Italian word origano, or possibly of the medieval Latin organum; this latter is used in at least one Old English work. Both were drawn from Classical Latin term origanum, which probably referred specifically to sweet marjoram, and was itself a derivation from the Greek origanon ὀρίγανον, which simply referred to "an acrid herb". The etymology of the Greek term is often given as oros ὄρος "mountain" + the verb ganousthai γανοῦσθαι "delight in", but the Oxford English Dictionary notes that it is quite likely a loanword from an unknown North African language.