As legend has it, Aphrodite, the Greek Goddess of love, planted oregano on Mt. Olympus. As a result, oregano became a symbol of love, which is why it's often used in Greek and Italian weddings. I think that's fitting, given that growing oregano is a joy. It makes a pretty addition to the garden, and it's indispensable in cooking.
Oregano is well known as a staple in Mediterranean sauces, especially those that are tomato based. My paternal grandparents both immigrated as young children from Italy in the early 1900s, so I was raised on delicious Italian dishes that featured oregano.
My grandmother used to make delightful oregano-herbed rolls. Oregano also works nicely with meat dishes such as baked fish and grilled lamb, and in vegetable entrees like baked zucchini.
Oregano has olive colored leaves and produces spikey purple flowers on taller varieties. Smaller plants often have flowers in whorls. The stems and leaves may be covered with a wooly looking fuzz. No matter what kind of flowers they have, all oregano plants attract bees and butterflies.
Oregano (Origanum vulgare) is part of the mint family. It is from the Mediterranean region of Europe which makes sense given its popularity in Italian and Greek dishes. It is closely related to wild marjoram (Origanum marjorana), and the two sometimes get confused.
There are many subspecies and different varieties of oregano. According to the Herb Society of America, there are 44 species, 6 subspecies, 3 varieties, and 18 naturally occurring hybrids. Look for those that are time-tested for culinary use if you plant to cook with your oregano.
Greek oregano (Origanum heracleoticum) is the standard culinary variety. It has a strong, sweet pungent smell. It's a low growing variety with white flowers. You may see this referred to as Mediterranean oregano.
Italian oregano (Origanum. majorana and Origanum vulgare) is milder tasting than Greek oregano. It has white or pink flowers and grows in a large clump that is two feet high and a foot and a half wide. It doesn’t do cold well and is hardy in zones 6-9.
Also known as Cretan oregano (Origanum onites), this variety is used for both culinary and ornamental purposes. It's tall, growing up to two feet in zones 5-9. The flowers attract bees and butterflies.
Dittany of Crete
Dittany (Origanum dictamnus) is the variety most often associated with herbal medicine and has a menthol odor. It's short, at six inches tall, and prefers warm weather. It also does well as a potted plant that you can bring indoors for the winter.
Mexican oregano (Lippia graveolens) is not true oregano, but I include it since you can substitute it in any dish requiring oregano. It is actually related to lemon verbena, and as such, it has the pungent overtones of oregano with a bit of a citrus flavor.
Species come in a variety of heights and weather tolerances, and their requirements can vary, so pay attention to the needs of the type you purchase.
Oregano is native to mountain areas with shallow, slightly acidic soil. It prefers a pH between 6.0-8.0. You can place wood ashes around oregano plants in the winter to help lower the soil acidity if you need to.
Oregano prefers soil that drains well. Sandy loam is perfect. If you have heavy clay like I do, then you can plant your herbs in a raised bed. I have a raised garden that holds oregano and thyme in the front with taller sage in the back because they have similar growing needs.
The advantage of growing oregano in a raised bed is that you can custom mix the soil. For my herb bed that contains oregano, thyme, and sage, I have a mix of native earth, sand, compost with a couple shovels of pea gravel to improve drainage.
Sun and Temperature Requirements
Oregano is a perennial, but it will act like an annual in cooler regions. Most varieties are hardy in zones 5–10 and prefer full sun to partial shade.
I am in zone 6, and I have growing oregano outside in my herb garden and in my greenhouse. The advantage of growing in my greenhouse is that sometimes a frigid winter will knock out my outdoor plants. I don't heat, or even close up my greenhouse all the way during the winter, but it still creates a hospitable microclimate for overwintering herbs and greens.
This method also gives me fresh leaves to use for winter stews and roasted root vegetables.
Planting can be started from direct seeding in the garden. You can transplant seedlings you have grown or purchased. You can also divide plants and get some roots from a garden friend.
To divide oregano, take a shovel and cut out a corner of the plant. You want your division to contain both roots and stem. If the weather is warm, it's also helpful to have some green leaves.
Plant your divisions in your garden as you would any other transplant.
If you are direct seeding, place the seeds on top of recently turned soil. Next tap them into place, so they are just under the topsoil’s crust. Sprinkle some dampened loss soil on top of them, so they are about 1/4 inch deep.
When growing oregano from seed, carefully check the seed's variety and growing requirements. Not all seeds grow true to type so buy from a reputable company.
When starting oregano indoors, use a light seed starting mix that contains vermiculite. Tap the seeds gently into the mix and cover lightly. Place your pots in a solid tray and water from the bottom.
Oregano will germinate quickly (4-5 days) if the temperature is above 70°F. You can use a heat mat to assist with germination if your grow room is chilly.
I start my herbs in peat pots since many cultivars do not like being transplanted. At planting time I gently remove the bottom of the pot and place in the hole.
You can usually buy oregano plants at your local garden store. One advantage of this is that you can give it the smell test. One disadvantage is that they will most likely have only one variety for sale.
Smelling the plants will help you determine if it will meet your needs. For instance, if you are looking for a culinary herb to make sauces, you may want a variety that smells sweet. If you are looking for one to use a medicinal herb, then you want one that smells astringent.
Plant oregano after the last frost date for your area when seedlings are about 3 inches tall. If your seedlings have been in a grow room or greenhouse, make sure to harden them off for about a week first.
Give growing oregano 6-12 inches between plants and 12-18 inches between rows, depending on the variety.
Oregano does well in containers, which is perfect if you live in an urban area or you want to grow them in the house over the winter. Some varieties such as ‘Kent Beauty’ look great in a hanging basket.
Remember that plants in containers or baskets often need more fertilizer. They have less space to grow in and less soil from which to gather nutrients.
Caring For Your Oregano
Oregano is not a thirsty plant, and it absolutely needs well-drained soil. Wait until the ground is dry before watering. Plan to give about an inch a week during dry spells.
Oregano does not need regular doses of fertilizer. It does well with an annual application of two inches of compost. If your leaves start turning yellow, try spraying with some fish emulsion.
Growing oregano doesn't need a thick much. Remember that it doesn't like dampness and mulch like straw retains moisture. Pebble or pea gravel is a better option if you want to suppress weeds.
The center of your growing oregano plant may become brown and dried up. This can happen every few years, especially with container or bed plants. At this point, you want to divide the plant.
Using a spade simply cut the plant in half. Add compost into the hole you created when removing half of the plant. Take the other half and replant in another location or share with a friend.
Problems and Solutions to Growing Oregano
Oregano is relatively problem free because its pungent oils tend to ward off pests. The biggest concern is fungal diseases. The best precautions are not to overwater and to have plants in a location with good air circulation.
Mint rust is a fungus that looks like little orange spots on leaves. It can cause leaves to turn brown and drop. The best way to control mint rust is to avoid it. Keep plants pruned and well-spaced, so they get plenty of air and avoid overhead irrigation. Keep your garden well weeded and water in the morning, so moisture has time to dry off. You can also prune off infected branches and destroy them.
Also known as gray rot, this fungus can spread through a garden rapidly. Plants may be covered in a gray mold and can shrivel up and die. Treat it as you do mint rust.
There's hardly any plant safe from this tiny pest. Aphids suck the juice out of plants, but the biggest problem is that they leave behind a secretion called honeydew that can encourage the growth of mold. Use neem oil to control them.
Cutworms nibble through plants at the soil line. To control, use a cardboard plant collar, spread diatomaceous earth around plants and keep weeds at bay.
Thrips can distort and discolor leaves. These insects can also transmit viruses. Control them with neem oil.
Spider mites are a common garden pest. They can cause leaves to yellow and drop off the plant, and you probably won't notice them until they've done some damage. Look for webbing and tiny little arachnids moving on leaves. You can blast them off your plants with a strong spray of water. Control with neem oil.
Companions for Oregano
Oregano is a great companion plant for many vegetables because it can help deter pests.
Avoid growing oregano near garlic or onions if you have a problem with thrips.
Harvesting and Storing Oregano
Pruning and harvesting go hand in hand. When you harvest, remove sprigs or small branches. This acts like pruning and encourages new growth. Harvest before the flowers bloom for the best flavor.
Wrap leaves in a damp paper towel and store in the refrigerator for a week. You can also freeze the leaves. Remove the leaves from the stems and wash and dry them. Place them in a plastic bag and press out all the air and put in your freezer where they won't get smashed.
Dried oregano is a handy staple to keep around. Tie a bunch of stems together and hang them upside down to dry.
Oregano as Herbal Medicine
Oregano has long been used in herbal medicine. The famous Ancient Greek physician Hippocrates named and described oregano in his work. Hippocrates used oregano as an antiseptic. Other uses from ancient times include treating GI problems and menstrual cramps.
The strong odor of oregano is caused by the essential oil carvacrol. Carvacrol is a creosote-scented compound that has antibacterial and anti-fungal characteristics. In addition, carvacrol is full of healthy antioxidants.
Recently scientific studies have shown that oregano has antimicrobial activity that kills food pathogens such as Listeria.