In the landscape, use oregano as a green foil for flowering herbs and perennials.
Native from Europe to Central Asia, the numerous types of oregano give you interesting options in the garden as well as in the kitchen. Some, such as golden oregano, are grown for their ornamental qualities. Others, such as Cuban oregano and Mexican oregano, are not true oreganos but are used like them. Italian and Greek oreganos are the preferred culinary types, their pungent flavor being an essential ingredient in Italian, Asian, Spanish, and Mexican cuisines.
In the Landscape
Most oreganos are shrubby plants that grow from 6 inches to 2 feet and have small, round, green leaves. While not particularly flashy, the larger plants provide a nice foil to brightly colored flowers, such as marigold or golden yarrow. Some oreganos have trailing habits that make them suitable as a ground cover or as an edging along a walkway. In the lower South, they may be evergreen. All selections spread easily and are drought tolerant, making them excellent for containers. Plants flower from July to September and feature small rose to white blossoms.
Planting and Care
Oregano likes full sun but will also grow in afternoon shade in the Middle South and farther south. The best way to start oregano is from transplants. Plant in well-drained soil with a pH of 6.0 to 7.0. Add a slow-release fertilizer before or during planting and work in again each spring.
Most types of oregano send out runners that will root as they grow; separate and transplant these. To start new plants, root stem cuttings taken in the spring or fall. Oregano can be grown from seed, but do not collect seeds from plants in the garden; purchase them. Plants in the garden often cross-pollinate, yielding unexpected results.
Harvest oregano often to encourage tender new growth. In the fall, remove tender selections from the ground to overwinter indoors. Plants left outside should be protected by mulch or a cold frame. Remove dead stems in the spring before new growth appears.
Species and Selections
There are several types of oregano whose appearance is easily confused with sweet marjoram. Some of the plants listed here are used as substitutes for oregano, but they belong to a different botanical genus.
Although oregano (Origanum species) is classified as a perennial, the least cold-hardy types are grown as annuals. Some oreganos are evergreen in the South, while others can be killed by frost.
Native to Greece, Greek oregano (Origanum vulgare Hirtum) is listed also as Origanum heracleoticum and is a popular selection of culinary oregano. Greek oregano is grown for its strong flavor and aromatic leaves. It is a tender perennial and needs to be protected with mulch in the winter in Zone 7 and south. Farther north, treat it as an annual. Greek oregano grows about 12 inches tall, with small, bright green leaves and white flowers. If grown with other selections, it will be overrun by the more vigorous, larger-leafed types. To promote a bushier plant, cut it back to one-third its size in late spring.
Italian oregano (Origanum x majoricum) is one of the most popular oreganos for culinary use. A perennial that grows 12 to 18 inches tall, Italian oregano has a flavor that is stronger than sweet marjoram but milder than Greek oregano. It is not reliably hardy north of Zone 6.
Also called Spanish oregano, wild marjoram (Origanum vulgare) is a hardy perennial that is evergreen through mild winters in the South. It is the most common oregano grown but not always the cook's favorite as its flavor can vary from weak to strong, depending upon the selection. Plants are bushy and shrublike, growing 1 to 3 feet tall, and bearing lavender or pink flowers in clusters, which are commonly dried and used as everlastings. This marjoram is often sold as seeds in packets and through mail order catalogues.
Golden oregano (Origanum vulgare Aureum) is a form of wild marjoram. It is grown as an ornamental and works well as a ground cover in shady areas. This oregano is not good for culinary use.
Although it is called marjoram, pot marjoram (Origanum onites) is a species of oregano. It has a sharp flavor that is stronger than other types when its leaves are used fresh. Pot marjoram is a shrubby perennial, growing to 2 feet tall with small gray-green leaves. If left outside in Zone 6 and north, pot marjoram will not survive the freezing temperatures.
Cuban oregano (Plecthranthus ambonicus), also listed as Coleus amboinicus or Spanish thyme, is not a true oregano, but it is a good substitute for Mediterranean oreganos. Fragrant, large-leafed, and frequently variegated, Cuban oregano is a tender perennial that cannot tolerate frost; grow it as an annual or in containers. Its large, succulent leaves are tolerant of sun and drought.
Mexican oregano (Poliomintha longiflora) is a strong-smelling plant popular in Mexico and Texas. Excellent for hot, humid areas, this woody shrub grows 3 feet tall. The small green leaves yield an essential oil similar to that of oregano and are used in cooking. Its tubular flowers of white to lavender blue attract hummingbirds.
Harvest, Storage, and Use
Harvest sprigs of oregano as soon as the plants reach 6 inches in height. If you want to harvest a large amount for drying, wait until just before plants bloom in midsummer. The flavor is most concentrated at this time. Cut the stems above the lowest set of leaves. Make another cutting in late summer after new foliage has sprouted.
Add oregano to Italian dishes, meat, cheese, fish, eggs, fresh and cooked tomatoes, zucchini, black beans, snap beans, and marinades. Sprinkle it lightly over salads before adding the dressing.
Use the flower stalks of oregano in wreaths and other crafts. Dry the foliage of Italian or Greek oregano for future culinary use. Strip leaves from stems after drying and store them refrigerated or frozen.
Oregano can suffer from aphids, fungus, root rot, and spider mites. To prevent disease, provide excellent drainage and remove diseased foliage promptly.