10.01.2008
Floriculture
By Thomas M. Blessington
David L. Clement and
Central Maryland REC
University of Maryland

Oregano, Origanum vulgare, is native to Europe, the Mediterranean and south-central Asia. A perennial herb, it normally grows 8 to 12 inches tall and has small white or purple flowers growing on long spikes. Hardy in zones 5 to 10, it is widely used in Greek and Italian cuisines. Oregano has antioxidant and anti-microbial activity.
Growth and development
Oregano requires well-drained media in full sun. It is drought tolerant; water once every week or two during dry periods. Oregano produces a stronger flavor if not fertilized. It can be grown indoors if provided with plenty of sun.
Propagation
Plant seeds indoors in mid-spring; cover only lightly with media as seeds require light to germinate. Transplant outdoors when temperatures remain above 45 degrees F. In cold climates, oregano is best treated as an annual. Space seedlings 12 inches apart, in rows 18 inches apart.
Disorders
• Spider mites — Wash leaves regularly.
• Aphids — Dislodge with a hard spray of water.
Consumer care
Sprigs can be taken once the plant reaches 4 to 5 inches in height. Harvesting before the plant blooms yields the most flavorful leaves. To harvest, cut stems down to the first two sets of leaves; new stems will grow and produce a second crop.
Leaves retain flavor best if added towards the end of cooking; flavor can become bitter if cooked longer than 30 minutes. Dried oregano has a stronger flavor than fresh.
Cultivars and species
• Origanum vulgare
‘Aureum’ has yellow leaves.
‘Hot and Spicy’ offers spicier flavor than common oregano.
‘Jim Best’ has green and gold variegated leaves; ornamental rather than flavorful.
‘Santa Cruz’ has green leaves and pink flowers; ornamental rather than flavorful.
• Lippia graveolens (Mexican oregano) has a similar flavor to common oregano, only stronger.
• Origanum heracleoticum (Greek oregano) — This variety is commonly used in Mediterranean cooking.
References
http://en.wikipedia.org/wiki/Oregano
www.gardenguides.com/plants/info/herbs/oregano.asp
http://gardening.about.com/od/plantprofil2/p/Oregano.htm
www.gardenersnet.com/herbs/oregano.htm
Mention of trade names does not constitute an endorsement by the Maryland Cooperative Extension, University of Maryland, College Park, or University of Maryland, Eastern Shore.