Marjoram is a popular addition to any herb garden, thanks to its sweet smell and kitchen usefulness. Butterflies and other insects love it, and the herb's light flavor makes it a popular ingredient in Mediterranean cooking.
Its oval-shaped, gray-green leaves and clusters of small white flowers are often confused with oregano. While the two plants look similar, one taste of marjoram, and you'll be able to tell the difference. Growing marjoram is easy: a healthy plant can reach up to two feet tall.
Marjoram thrives in loose, well-draining soil, but it can survive in poor-quality dirt as long as it isn't overwatered. If you're starting your marjoram from seeds, sow them indoors about four weeks before the last expected frost, planting them a 1/4-inch below the soil. Marjoram seeds take a while to germinate, so this gives you a bit of a headstart. After the last frost, it's safe to transplant the seedlings to the garden. If you plan to cook with your marjoram, plant at least three plants.
When planting marjoram outside, arrange the plants in rows at least 18 inches apart with at least six inches between each plant. To get the best growth and flavor from your marjoram, prune it back in late spring before the flowers start to develop and again in later summer. If you don't cut it back occasionally, marjoram will spread and take up a lot of space in your garden. You can also grow marjoram in a container, but make sure it's at least six inches deep.
Marjoram can tolerate a bit of shade, but this is a summer plant that thrives with at least six hours of direct sunlight. The plant is native to the Mediterranean region — similar weather to United States zones 9 and 10 with an average low temperature that doesn't get below 20 degrees F. That said, this hardy plant will thrive in zones 6 to 11. Zone 6 is a moderate climate where temperatures can get as low as -10 in the winter, while zone 11 covers hot climates like Hawaii and Puerto Rico, where the winter temperatures rarely dip below 40 degrees F.
As you can see, this plant is pretty versatile!
After first planting or transplanting marjoram, water it regularly. Once the plant is established, cut back significantly, watering only when the soil is completely dry. Marjoram is a drought-tolerant plant and can tolerate a bit of neglect. As with most plants, overwatering is significantly worse than underwatering. Not only can it lead to problems with the plant's health, but it also affects the flavor of the herb.
In general, marjoram is easy to care for and doesn't require any special treatment, though you may want to feed it half-strength fertilizer at the beginning of the summer.
Marjoram doesn't have many serious pest issues, but some common garden pests to look out for include aphids and spider mites. An aphid infestation causes the leaves to turn yellow and mold to grow. You'll usually be able to see the small, soft-bodied insects stuck to the bottom of the leaves.
Spider mites can cause the leaves to turn yellow or bronze and appear as tiny dots moving on the underside of the leaf. You can usually eliminate infestations of aphids or spider mites by spraying them off the plant with water.
Marjoram is a pretty hardy plant and isn't affected by many diseases, but there are a few things to look out for. Mint rust can spread to other plants and kills large parts of leaf tissue. Look for small yellow or orange pustules on the bottom of the leaves.
Another disease that affects marjoram is blight, a fungus that first appears as soft brown spots and then advances to gray mold. To avoid blight, ensure your marjoram has plenty of air circulating around it and avoid splashing the leaves when watering.
Propagating marjoram is pretty easy, and it's a great way to keep your plant going indoors throughout the winter. Take a cutting by looking for a node on the softwood or semi-hardwood parts of the plant. These are the areas of the stalk where it's still green or green/brown and bends easily.
Water your plant the day before you take a cutting and take more than you think you'll need — each cutting should be between two and four inches long. Cut the end at an angle and then place it in potting soil, keeping the soil moist but not wet until roots form.
To harvest marjoram, snip off the shoots where the flowers have not yet begun to open to get the best flavor. That said, you can harvest any branch you want, but the taste may be a bit bitter if the flowers have fully opened. Marjoram is usually ready to harvest about five weeks after transplanting outside.
If you're harvesting marjoram to use in the kitchen, keep it fresh in the refrigerator for up to four days. To get the best flavor, dry the leaves, then store them in an airtight container. You can do this by covering the marjoram with a paper towel on a baking sheet and putting it in the refrigerator or leaving the leaves in an uncovered bowl for as many as seven days. You can also hang them in a warm, dry place to dry.
Marjoram makes a great seasoning for meat but is versatile enough to use with vegetables, too. It's a common addition to tomato-based dishes and salad dressings.
Keep in mind that the flavor of dried marjoram is very concentrated, and it can take time to develop. Add it early in the cooking process to make sure it has enough time to intensify. For fresh marjoram, it's the opposite. Add it later in the cooking process so that the flavor doesn't disappear before you're ready to serve your meal.