University of Illinois Extension
  List of Common Herbs:Oregano - Herb Gardening - University of Illinois Extension

Greek Oregano

oregano

Origanum vulgare var. hirtum

Perennial

Description

There is much confusion concerning the difference between oregano and marjoram.  To many, oregano is more of a flavor than any one individual plant. However, if you want to plant “true” oregano, Greek oregano is the one to plant.  Oregano is a loose, open plant growing from six inches to two feet tall with gray-green leaves and small purple or white flowers.  Common marjoram, often sold as wild oregano, is a hardy rampant growing perennial.  It is more of an ornamental herb as it is considered to be inferior for use as a culinary herb.

Culture 

Oregano can be grown from seed or cuttings.  Seed propagated plants often do not come true from seed so it is suggested to obtain plants grown from cuttings.  These cuttings are taken from plants with high flavor quality.  If seeds are sown, place seeds on top of the growing media and press them into the surface.  Do not cover the seeds as light is needed for germination.  Keep moist.   Oregano must be planted in a full sun location and good drainage is required for best growth and overwintering.  True oregano is marginally hardy in zone 5.  Many of the really desirable types are treated as tender perennials and may need to be brought indoors for the winter.  To help insure winter survival a winter mulch of evergreen boughs or straw applied in November or December after the soil has frozen is helpful.  This is then removed as growth resumes in the spring.  

Harvesting

Harvesting can begin just before the plants are ready to flower.  Remove the stem tips leaving 4-6 pairs of leaves on the plant in order for it to produce side shoots for additional harvesting.  This will also help to make the plant become bushier and more compact.  Allowing the plant to flower will reduce or stop growth completely. It also reduces the flavor of the leaves. Hang the cut stems in a cool, dry, dark well-ventilated location.  After leaves are dry, they can be removed from the stems and stored in sealed containers. 

Uses

Oregano is used in sauces, tomato dishes, pizza, Mexican dishes salads and soups.  

Popular Varieties

  • ‘Profussion’ ® oregano – Very hardy, with an intense flavor.
  • Greek Oregano – True oregano, excellent flavor, hardy.

Other useful types but not as winter hardy.  May have to be treated as a tender perennial or brought indoors for the winter.

  • Syrian Oregano (Oregano maru) - Strong, spicy flavor.
  • Turkestan Oregano (Oregano tyttanthum) - Strong flavor, robust plant, good for indoor culture.
  • Hopley’s Purple Oregano – Purple-green foliage, compact, mild flavor.
  • Mexican Oregano (Lippia graveolens) – Good oregano flavor used for chili and Mexican dishes.