Peg Godwin: Is it oregano?

By Peg Godwin
Extension Agent, Agriculture - Horticulture
Lenoir County, NC
peg_godwin@ncsu.edu

Oregano is a common culinary and medicinal herb from the mint family (Lamiaceae). It has been used in medicine and cooking for thousands of years. My recent discovery about oregano has surprised me.

Origanums are native to the Mediterranean and Eurasia and grow in mountainous areas with rocky, calcareous soil. Sizes vary from only a few inches high to 39 inches tall. Both the stems and leaves of origanums are often covered with fine hairs. Leaves have various shapes including round, heart-shaped and oval as well as different textures. Leaf surfaces may appear shiny or waxy or hairy/fuzzy. Stems may be woody or non-woody.

Linnaeus originally classified Origanum within the mint family as a single genus. Now, the oregano genus also includes Amaracus and Majorana because these herbs are so similar. They are more commonly known as the herbs oregano and sweet marjoram but include more than 25 different plants.

These plants vary in flavors, size, color and their fragrance and get their flavor from the volatile oils, which are best preserved when the oregano leaves are dried on the branch and crushed as needed.

There are several species of oregano that are commonly used in cooking, included Mexican oregano or Origanum genus, Italian Oregano or Origanum x majoracum, and Oraganum libanoticum, which is primarily used as an ornamental plant.

Dr. Arthur O. Tucker recommends thinking of oregano as a flavor instead of just one genus or species of similar plants. Oregano and marjoram are common herbs but have a very complicated taxonomic history.

Plectranthus amboinicus, once identified as Coleus amboinicus, is a semi-succulent perennial plant in the family Lamiaceae with a pungent oregano-like flavor and aroma. It is native to Southern and Eastern Africa. There are many common names for this plant: Indian borage, Spanish Thyme, Caribbean oregano, Cuban oregano and Mexican mint. This plant is hardy in zones 10 through 11 and thrives in full to partial sunlight and in soil that is fast-draining and nutrient-rich.

Variegated Oregano (Origanum vulgare) is a low growing herb with a mounding habit. It is a small plant, reaching about 14 to 18 inches high and approximately 8-10 inches wide. The creamy white flowers are small and insignificant but are bee and butterfly attractants. This plant is sometimes listed as variegated marjoram, which may cause confusion. It is also important not to confuse 0. vulgare — variegated with Variegated Cuban Oregano which is actually a different species.

There are many different varieties of oregano, each with different characteristics and culinary uses. Oregano also has powerful healing properties including use as a painkiller, anti-septic and anti-inflammatory. There are other plants that also contain similar flavors and aromas.