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oregano (Origanum vulgare)

Origanum vulgare is an aromatic, branching perennial herb to subshrub that can become woody at the base, with stems that are often four-angled. It is perennial, although it is sometimes grown as an annual in colder regions.

LightFull sun is preferred, although some horticultural varieties can accept partial sun.
WaterKeep conditions on the dry to moderately moist side with good drainage; after establishment, avoid excessive drying as well as prolonged wetness or waterlogging.
HumidityIt is generally reported to prefer low humidity and need good airflow.
TemperatureSources differ, with limited evidence indicating a minimum temperature of about -20 °C. Sources differ in their hardiness classifications, while Origanum vulgare is described as frost hardy.
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oregano illustration

Overview

Origanum vulgare is an aromatic, branching perennial herb to subshrub that can become woody at the base, with stems that are often four-angled. It is perennial, although it is sometimes grown as an annual in colder regions.

Origin and habitat

Sources differ on its native range: major sources place it from Europe and the Mediterranean region through western Eurasia into parts of Asia, while other compiled records also include North Africa, West Asia, Central Asia, the Caucasus and Siberia, and TaiCOL regards populations in Taiwan as native. It occurs in dry grassland, scrub, hillside grassland, roadsides, rocky ground, wasteland and woodland edges, with some sources noting an association with calcareous soils. It prefers sunny, relatively warm and dry conditions, has some cold and drought tolerance, and does not favor hot, humid or persistently wet conditions.

Characteristics

Sources differ on mature height, placing it at about 20–90 cm, while mature spread is 50–100 cm. Sources describe the opposite leaves somewhat differently; they are generally ovate to elongated ovate and green to dark green, may be hairy or gland-dotted, and can have entire to slightly toothed margins. Sources differ somewhat in their descriptions of the small tubular or lipped flowers, which are commonly pink, pale purple, purplish red or white and form dense terminal or branched clusters; flowering occurs mainly from summer into early autumn. The fruit is reported to be a small ovoid nutlet.

Light

Full sun is preferred, although some horticultural varieties can accept partial sun.

Watering

Keep conditions on the dry to moderately moist side with good drainage; after establishment, avoid excessive drying as well as prolonged wetness or waterlogging.

Humidity and airflow

It is generally reported to prefer low humidity and need good airflow.

Temperature and dormancy

Sources differ, with limited evidence indicating a minimum temperature of about -20 °C. Sources differ in their hardiness classifications, while Origanum vulgare is described as frost hardy.

Growing medium and mounting

Well-drained, relatively dry soil is preferred; it can grow in sandy loam, loam and chalky soils and tolerate relatively poor soil, while some sources indicate a preference for slightly alkaline or calcareous conditions.

Feeding

Fertilizer needs are low, and the plant can grow in relatively poor soil with sufficient sun; excessive fertilizer may increase the risk of leaf spotting and weaken its aroma.

Propagation

It is reported to be propagated by seed, division in spring, or cuttings in early summer.

Common problems

High humidity, overly dense growth or excessive fertilizer is reported to be associated with bacterial- or mold-related leaf spotting that can produce black spots on the leaves. High humidity and prolonged rain are reported to cause persistently damp conditions, weakening the plant and potentially causing dieback from the base; insufficient light, prolonged rain or excessive fertilizer may also weaken its aroma. It tolerates drought and cold but does not favor prolonged rain, high humidity or persistently wet conditions.

Identification

It is reported to have a distinct aroma throughout the plant, often four-angled hairy stems, opposite leaves and small clustered flowers; its essential oil can contain carvacrol and thymol.

Photos

Origanum vulgare
📷 unknown · Public domain · source
Origanum vulgare
📷 Ivar Leidus · CC BY-SA 4.0 · source
Origanum vulgare
📷 Mickaël Schauli · CC BY-SA 4.0 · source

Sources