When I give my presentation on culinary herbs I always talk about oregano and marjoram together. I treat them as cousins, and in this country, they are most known for the “oregano” flavor. Although we use the term “oregano” for a specific type of culinary herb, it really is a flavor produced by different types of plants. Some of these are not related to what we think of as the oregano plant.
The Origanum genus is in the mint family, Lamiaceae. There are more than 40 species and many varieties and hybrids – they cross pollinate easily. All have typical “mint” flowers: bilaterally symmetrical with five united petals that create an upper and a lower lip. The small flowers occur in spikes and attract beneficial insects and pollinators. Some plants have bracts or modified leaves that are more pronounced and colorful than others (poinsettia and bougainvillea are examples of colorful bracts that look like flowers but are not true flowers). They all have hairy stems and leaves and again, some more so than others.
Of the culinary herbs in the Origanum genus, all hail from the Mediterranean area, thus requiring full sun, well-drained soil, and good air circulation. Not all are hardy here in the mid-Atlantic area but they are all deer resistant because of their chemical constitution. These plants have two primary chemicals: carvacrol and sabinene hydrate. Some have thymol. Carvacrol is responsible for the pungent, peppery flavor you know so well from “pizza oregano.” It is a creosote-scented phenol with antibacterial and antifungal properties. The amount in each plant varies.
If you are purchasing a plant for culinary use, crush a leaf, and smell and eat it first before you purchase the plant. You want to ensure it has the right amount of carvacrol for your palate. You want to do this so you don’t accidently purchase Origanum vulgare, which is a common oregano type plant that has naturalized in this area. Although edible, it is not considered “tasty” because of its low level of carvacrol. It can still be grown as an ornamental in the garden and has small pink flowers (not white) in the summer.
For the best flavor, buy Origanum vulgare subsp. hirtum, which is Greek oregano, or Origanum x majoricum, which is Italian oregano. Both have a high levels of carvacrol. Both are hardy to this area and make great landscape plants. These plants have small white flowers on inch-long terminal flower structures and provide greenery above ground in the winter.
In the front of my house, I have Greek oregano. From spring to summer, there is new growth and the stems grow upright. In the early summer, right before it flowers, the branches can be cut to harvest the leaves. The plant rebounds quickly and although it is possible to get a second harvest, I let mine flower. By summer, the branches topple over with the weight of the flowers. The area is surrounded by insects and bees. By late fall it gets a little ratty looking and I cut back the flower stalks. The plant remains above ground in the winter and the foliage turns purple. Every year, a baby plant pops up in the front garden which is easy to pull and either throw away or pot up and give to a friend.
I was given ‘Hot and Spicy’ which is a cultivar of Greek oregano. I find it too pungent and peppery so I grow it in the backyard, against the tool shed. It receives morning shade and afternoon sun but still flowers. I don’t harvest it, I just let it flower to attract the pollinators for my vegetables nearby.
Next to my Greek oregano is sweet or knot marjoram. Marjoram has a low level of carvacrol and but a high level of sabinene hydrate, which is more of a fruity flavor. Marjoram is so sweet it is used in perfume as well as baking and cooking. In the past, marjoram was employed as a strewing herb, incorporated in potpourris and sachets, and used to scent linen closets and hope chests. It is called knot marjoram because the flower buds are knots; like knots used as buttons on shirts.
Marjoram is considered a tender perennial and should not survive our winters but mine has lived for many years in my Virginia, zone 7 garden. I am sure it is because it is in full sun on a terraced area so it has very good drainage and warmth from the south side of the house. Marjoram grows like the Greek oregano. By fall the branches bow down with the weight of the flowers, also surrounded by insects. However, in the winter, the foliage is green, not purple, and I have never seen a baby marjoram pop up in the garden.
Next summer, I plan to purchase Italian oregano which is a cross between marjoram (O. majorana) and Greek oregano (O. vulgare subsp. hirtum). It should be not as spicy and hot as the Greek oregano because O. majorana’s sweetness tempers it. Many culinary herbalists recommend this one for cooking.
There are two other types of oregano that are great for cooking which I would like to grow next year: O. onites and O. syriacum. These are tender perennials that will not survive winter. I don’t expect them to be in our local nurseries, either as they are not well known here. O. onites is called pot marjoram or Turkish oregano. It is high in carvacrol and thymol so it has a strong, peppery, thyme flavor. It is a pretty plant that grows to about 1 ½ feet tall, with small rose/white flowers peeping out of the enlarged, purple bracts.
O. syriacum, also called za‘atar or Syrian or Lebanese oregano, has less carvacrol and more thymol so is not as peppery. It has very hairy leaves, creating a silver appearance, and small white flowers. The plant grows to about 2 feet tall. This is the plant used to make za ‘atar, which is also a term for a blend of spices and herbs.
If you do not have a garden, all of these plants can be grown in containers for the summer. Make sure the container is in full sun and large enough with drainage holes. You may have to water more often than if they were in the ground.
In the kitchen, you can use fresh or dried foliage from these plants. The herb flavor is always stronger in dried leaves so use less of the dried than of the fresh leaves. These plants add flavor to yeast breads/rolls, savory scones with cheese, focaccia, garlic bread, egg dishes, bean dishes, tomato-based dishes, potatoes, cornbread/muffins, and corn or tomato soup. They pair well with thyme and/or lemon or olive oil or garlic and/or lemon. You can make a rub by mixing with other herbs to rub over chicken, turkey, or pork before roasting. You can also add to stuffing or dressing. The branches can be used to decorate a turkey platter or a side dish.
Try growing marjoram and oregano in your garden this summer. You will enjoy their flavor in your dishes and you will be able to support pollinators and beneficial insects in the garden. For more information on purchasing and growing herbs in the DC metro area, as well as herb cookbooks, click here. If you are interested in learning more about culinary herbs, join the Facebook group called Culinary Herbs and Spices or join the Potomac Unit of the Herb Society of America.