O is for Origanum

"Origanum" is the herb Oregano (sometimes called wild marjoram).  Greek for "joy of the mountain," oregano was almost unheard of in the United States until soldiers came back from Italian World War II assignments raving about it.

European Oregano (Origanum vulgare) is the most bland.  Greek Oregano (Origanum herva-cleoticum) is the most common for cooking.  Both belong to the mint family and are related to both marjoram and thyme. Mexican Oregano (Lippia graveolens) is in the verbena family and is one of the most spicy.  The Mexican variety is included in chili powder.  Golden Oregano is used for it's decorative look and not for eating.  Some are hardy to Zone 5.

You may find some oregano mislabeled: 

Mexican Oregano can mean Poliomintha longiflora.  It is considered similar in flavor, but stronger than oregano.

• In Puerto Rico and Cuba, Plectranthus anboinicus can be found labeled as oregano.
• Thymus nummularius is often used in place of oregano, in Spain.  It is used in perfume.

If you are planning on making tomato based sauces, plant Oregano in your herb garden this year.  The leaves of oregano are used in meat (especially sausage), salads, pizza, soups, Mexican foods and barbecue sauces.   It is also used in making some kinds of liqueur.

Factors such as climate, seasons and soil composition may affect the aromatic oils present, and this effect may be greater than the differences between the various species of plants.

Some oregano is a tender perennial and may be over-wintered inside.  Try cutting down and heap mulch on top for over-wintering - just might make it through.  In the south, it may be invasive. 

Oregano leaves are often used in the dried form for cooking - although they may be used fresh as easily.  The dried form may be more flavorful than fresh although it's a different flavor.

The leaves retain their flavor better in hot dishes if added toward the end of cooking. Heating too long results in bitterness.

Oregano grows easily in well drained, good garden soil where plants receive full sun. They enjoy a sandy soil.  It requires routine watering. The flowers should be kept cut back to encourage thick foliage - the level of essential oil decreases as it flowers. You can begin to harvest when it reaches 4 inches.  It makes a good container or hydroponic plant but should be replaced about every 3 years when it becomes woody. 

Oregano planted from seeds may cross pollinate and you may not get what you expected.  The "richer" the soil, the less potent the flavor - do not fertilize.  Oregano has few pests.  Keep area weeded and mulched.  May be added to flower gardens.  Pick in the morning before the leaves warm to get the best flavor.

An idea:  Put a 1/2 inch thick slice of feta cheese on a salad plate. Serve it sprinkled with oregano (and fresh pepper if you like), and drizzle with olive oil.  Serve with flat bread or crackers.

And in case you need this:   From Gerard's Herbal (1545-1612-English): "Organy cureth them that have been poisoned by drinking Opium, or the juice of Black Poppy or Hemlock, especially if it be given with Wine and Raisons of the Sunne".

Photos thanks to Herb World.