Rosemary

Rosmarinus officinalis (syn. Salvia rosmarinus)

Common & Folk Names

• Garden Rosemary
• Old Man
• Compass Plant
• Polar Plant
• Dew of the Sea (from Latin ros marinus)
• Mary’s Mantle
• Incensier (French)

Plant Family

Lamiaceae (Mint Family)

Geographic Location

Native to the Mediterranean region, particularly coastal areas of southern Europe and North Africa. Now widely cultivated throughout temperate and subtropical regions worldwide, including extensively in New Zealand gardens.

Habitat

Rosemary thrives in sunny, coastal environments with well-drained soil. In its native habitat, it grows on rocky hillsides and cliffs near the sea. It tolerates salt spray, drought, and poor soils, but dislikes heavy clay or waterlogged conditions.

Growing Conditions

Sun: Full sun is essential for optimal growth and oil production

Soil: Well-drained, slightly alkaline to neutral pH (6.0-7.5). Sandy or gravelly soils are ideal. Poor to moderately fertile soil produces more concentrated oils than rich soil.

Propagation: Easy from semi-hardwood cuttings (spring or autumn) or layering. Can be grown from seed but germination is slow and variable.

Care: Prune regularly after flowering to maintain shape and encourage bushy growth. Avoid cutting into old wood as it doesn’t readily resprout. Drought-tolerant once established but appreciates occasional deep watering in very dry periods.

NZ Planting Calendar

Propagation (cuttings): Spring to autumn (September–April) – semi-hardwood cuttings root easily

Propagation (layering): Autumn to spring (March–November)

Planting: Spring (September–November) or autumn (March–May)

Growth: Evergreen perennial shrub; frost-hardy once established

Flowering: Mainly winter to spring (June–November); can flower sporadically year-round

Harvest (leaves/stems): Year-round; best just before or during flowering for maximum oil content

Note: Not native to NZ; Mediterranean herb thriving in NZ conditions; prefers well-drained soil and full sun

Harvesting Guidelines

Harvest leafy stems throughout the growing season, but volatile oil content peaks just before flowering (typically spring in NZ). Morning harvest after dew has dried but before full sun heat provides the best oil concentration. Use fresh or dry for storage. Regular harvesting encourages bushier growth.

Parts Used

• Leaves
• Flowering tops
• Essential oil (steam-distilled from leaves and flowers)

Constituents & their Actions

Volatile Oils:

These aromatic compounds are responsible for rosemary’s distinctive scent and many of its therapeutic properties. The volatile oil content ranges from 1-2.5% in dried leaves. Some of the main volatile oils in rosemary are:

• 1,8-cineole (eucalyptol): 20-50% of essential oil
• Camphor: 10-25%
• α-pinene: 9-26%
• Borneol
• Bornyl acetate
• Camphene
• Limonene
• Linalool

The main actions of these volatile oils are:

• Antimicrobial (particularly antibacterial and antifungal)
• Stimulates circulation (especially to the brain and periphery)
• Antispasmodic (relaxes smooth muscle)
• Carminative (relieves intestinal gas)
• Mild analgesic
• Cognitive enhancement

Phenolic Diterpenes:

These unique compounds are among rosemary’s most important medicinal constituents, providing powerful antioxidant and anti-inflammatory effects. Some of the main phenolic diterpenes in rosemary are:

• Carnosic acid: 1.5-2.5% dry weight
• Carnosol: 0.3-0.4%
• Rosmanol
• Rosmaridiphenol

The main actions of these phenolic diterpenes are:

• Potent antioxidant (among the strongest plant-derived antioxidants)
• Neuroprotective (protects brain cells from oxidative damage)
• Anti-inflammatory
• Hepatoprotective (protects liver cells)
• Anti-cancer activity (in laboratory studies)

Flavonoids:

These polyphenolic compounds provide additional antioxidant activity and support vascular health. Some of the main flavonoids in rosemary are:

• Diosmin
• Apigenin
• Luteolin
• Genkwanin

The main actions of these flavonoids are:

• Antioxidant
• Anti-inflammatory
• Supports capillary strength and reduces permeability
• Mild antispasmodic

Phenolic Acids:

These compounds contribute to rosemary’s antioxidant and antimicrobial properties. The main phenolic acid in rosemary is:

• Rosmarinic acid: 2-3% dry weight

The main actions of rosmarinic acid are:

• Antioxidant
• Anti-inflammatory (inhibits leukotriene synthesis)
• Antimicrobial
• Antiallergic (reduces histamine release)

Triterpenes:

These compounds contribute to anti-inflammatory and hepatoprotective effects. Some of the main triterpenes in rosemary are:

• Ursolic acid
• Oleanolic acid
• Betulinic acid

The main actions of these triterpenes are:

• Anti-inflammatory
• Hepatoprotective
• Antimicrobial

Actions with Mechanisms

Cognitive Enhancement & Neuroprotection:
The volatile oils in rosemary, particularly 1,8-cineole, readily cross the blood-brain barrier when inhaled or ingested. Once in the brain, 1,8-cineole inhibits acetylcholinesterase, the enzyme that breaks down acetylcholine, which in turn increases acetylcholine availability for memory and learning processes. Additionally, carnosic acid and carnosol protect neurons from oxidative stress by activating the Nrf2 pathway, which upregulates antioxidant enzyme production. This dual action–neurotransmitter support plus cellular protection–makes rosemary valuable for memory, concentration, and potentially for age-related cognitive decline prevention.

Circulatory Stimulant:
The volatile oils, particularly camphor and 1,8-cineole, stimulate peripheral circulation by causing mild vasodilation. This occurs through their warming effect on tissues and their interaction with temperature-sensing receptors (TRP channels), which in turn triggers increased blood flow to areas where rosemary is applied topically or to the extremities when taken internally. This action makes rosemary useful for cold hands and feet, and for delivering more oxygen and nutrients to tissues.

Antioxidant:
Rosemary contains some of the most potent antioxidants in the plant kingdom. Carnosic acid and carnosol neutralize free radicals by donating hydrogen atoms, which in turn stabilizes these reactive molecules and prevents them from damaging cellular components like DNA, proteins, and lipid membranes. Additionally, these compounds activate the Nrf2-ARE pathway, which increases the cell’s production of its own antioxidant enzymes including superoxide dismutase, catalase, and glutathione peroxidase. This creates a sustained antioxidant effect beyond the initial free radical scavenging.

Antimicrobial:
The volatile oils in rosemary, particularly 1,8-cineole, α-pinene, and camphor, disrupt bacterial and fungal cell membranes by inserting into the lipid bilayer. This increases membrane permeability, which in turn allows cellular contents to leak out and disrupts the microorganism’s ability to maintain proper osmotic balance, leading to cell death. Rosemary shows particular effectiveness against gram-positive bacteria including Staphylococcus aureus and various food-borne pathogens, as well as common fungi like Candida albicans.

Anti-inflammatory:
Rosmarinic acid and carnosol inhibit several inflammatory pathways simultaneously. They block the COX-2 enzyme (similar to NSAIDs but more gently), which reduces prostaglandin production. They also inhibit 5-lipoxygenase, which decreases leukotriene formation. Additionally, these compounds suppress NF-κB activation, a master switch that controls many inflammatory gene expressions. This multi-targeted approach, which works through these combined mechanisms, reduces both acute and chronic inflammation throughout the body.

Digestive Stimulant & Carminative:
The bitter compounds in rosemary stimulate taste receptors on the tongue, which in turn triggers a reflex that increases gastric acid, bile, and pancreatic enzyme secretion. This enhances digestive function and nutrient absorption. The volatile oils also relax the smooth muscle of the gastrointestinal tract, which helps expel trapped gas and relieves bloating and cramping. The antimicrobial properties additionally help maintain healthy gut flora balance.

Analgesic (Pain Relief):
When applied topically, rosemary’s volatile oils penetrate the skin and interact with peripheral nerves. Camphor and 1,8-cineole create a mild counter-irritant effect, which stimulates sensory receptors that override pain signals through the “gate control” mechanism. Additionally, the anti-inflammatory compounds reduce inflammatory pain by decreasing prostaglandin production at the site of discomfort. This makes rosemary useful for muscular aches, joint pain, and headaches.

Hepatoprotective (Liver Protection):
Carnosic acid and carnosol protect liver cells through multiple mechanisms. They induce phase II detoxification enzymes, which enhance the liver’s ability to neutralise and eliminate toxins. They also protect hepatocytes from oxidative damage by scavenging free radicals and increasing cellular antioxidant defenses. Furthermore, these compounds have been shown to reduce fibrosis and support liver cell regeneration after toxic injury in animal studies.

Main Use

Rosemary’s primary uses are as a cognitive enhancer and circulatory stimulant to support memory, concentration, and mental clarity, particularly during mental fatigue or when studying. It’s also widely used topically in diluted essential oil form or as an infused oil for muscular aches, joint pain, and to stimulate circulation to cold extremities. Internally, rosemary acts as a digestive bitter and carminative to support healthy digestion, relieve gas and bloating, and stimulate appetite. Its potent antioxidant properties make it valuable for general cellular protection and potentially for supporting healthy aging.

Preparations

Tea/Infusion: 1-2 teaspoons of dried leaves (or a 10cm sprig of fresh) per cup of boiling water. Steep covered for 10-15 minutes to preserve volatile oils. Drink 1-3 cups daily before or with meals for digestive support, or mid-morning/early afternoon for cognitive enhancement. The tea has a pine-like, slightly bitter, aromatic flavor.

Tincture: (1:5 in 45-60% alcohol). The higher alcohol percentage is needed to extract both the volatile oils and resinous compounds effectively. Dose: 2-4ml (40-80 drops), 2-3 times daily. Best taken in a small amount of water.

Essential Oil (Aromatherapy): Add 3-5 drops to a diffuser for cognitive support during studying or work. The aroma alone has been shown to improve memory performance and alertness in clinical studies. Never ingest undiluted essential oil.

Infused Oil (Topical): Pack a jar with dried rosemary leaves, cover with olive or sweet almond oil, and infuse for 4-6 weeks, shaking daily. Strain and use as a massage oil for sore muscles, stiff joints, or to improve circulation. This can be made into a warming balm by adding beeswax.

Hair Rinse: Strong infusion (3-4 tablespoons of herb per litre) cooled and used as a final rinse after shampooing. Traditionally used to darken hair, add shine, and support scalp health. The antimicrobial and circulation-stimulating properties may support hair growth.

Culinary: Liberal use in cooking provides mild therapeutic benefits while adding flavor. The act of cooking doesn’t destroy all beneficial compounds, though it does reduce volatile oil content.

Dosage

Dried Herb (Tea): 2-4 grams (approximately 1-2 teaspoons), 2-3 times daily

Tincture (1:5, 45-60%): 2-4ml (approximately 40-80 drops), 2-3 times daily

Essential Oil (Aromatherapy): 3-5 drops in diffuser as needed

Topical Use: Infused oil or diluted essential oil (2-3 drops essential oil per teaspoon carrier oil) applied to affected areas 2-3 times daily

Safety & Drug Interactions

Scientific Evidence

Cognitive Enhancement: Multiple human clinical trials have demonstrated that rosemary aroma significantly improves memory performance and alertness. One study showed that people working in cubicles infused with rosemary essential oil demonstrated better memory performance on standardized tests. Another found that 1,8-cineole levels in the blood correlated directly with cognitive performance improvements. The effects appear to be dose-dependent and most pronounced for prospective memory (remembering to do things).

Antioxidant Activity: Laboratory studies consistently show that rosemary extracts, particularly carnosic acid and carnosol, are among the most potent plant-derived antioxidants. These compounds have shown effectiveness in protecting cells from oxidative damage in numerous in vitro studies. This antioxidant activity is so significant that rosemary extract is used commercially as a natural preservative in foods and cosmetics.

Anti-inflammatory & Analgesic: In vitro and animal studies demonstrate that rosemary compounds inhibit inflammatory pathways (COX-2, 5-LOX, NF-κB). Human studies on topical application for pain are limited but show promise. One study found that rosemary oil massage reduced pain in patients with rheumatoid arthritis. The mechanisms are well-established even though large-scale human trials are still needed.

Antimicrobial: Extensive laboratory research confirms rosemary essential oil’s effectiveness against a broad spectrum of bacteria and fungi, including antibiotic-resistant strains like MRSA. The minimum inhibitory concentrations vary by organism but are generally in the range that makes rosemary useful for topical antimicrobial applications and food preservation.

Hepatoprotective: Animal studies show that carnosic acid protects liver cells from various toxic insults, reduces fibrosis, and may support liver regeneration. Human studies are limited, but the mechanisms are well-documented in experimental models. This suggests potential benefit, but clinical confirmation is needed.

Digestive Support: While direct clinical trials on rosemary for digestion are sparse, the bitter and carminative properties are well-established through traditional use and understanding of the mechanisms involved. The antimicrobial effects on gut pathogens are supported by laboratory studies.

Evidence Level: Strong for cognitive enhancement (human trials) and antioxidant activity (extensive laboratory evidence); Moderate for anti-inflammatory and antimicrobial uses (in vitro and animal studies, limited human trials); Traditional use for digestive support is mechanistically sound.

Western Energetics

Temperature: Warming. Rosemary strongly stimulates circulation and metabolism, creating heat in the body. It’s indicated for “cold” conditions including poor circulation, cold extremities, mental sluggishness, and digestive weakness from insufficient heat.

Moisture: Drying. The volatile oils and astringent tannins have a desiccating effect, making rosemary useful for conditions with excess dampness such as edema, loose stools, excessive mucus, or torpid digestion.

Tissue State: Primarily for Depression/Atony (sluggish, under-functioning tissues) and Cold/Stagnation. Rosemary excels at stimulating tissues that are sluggish, congested, or under-functioning–whether that’s mental fog, poor digestion, or cold, stiff joints.

Taste

Pungent: The primary taste, derived from volatile oils. This pungency indicates rosemary’s warming, stimulating, and dispersing qualities. The pungent taste is said to activate circulation and clear stagnation.

Bitter: A strong secondary taste, particularly noticeable when chewing fresh leaves. This bitterness signals rosemary’s digestive-stimulating properties and cooling effect on inflammation, which balances its overall warming nature.

Slightly Sweet: A subtle undertone from the aromatic compounds, which provides a grounding quality to balance the intense pungent and bitter tastes.

Plant Lore

Rosemary has been steeped in symbolism for thousands of years. In ancient Greece, students wore rosemary garlands while studying, believing it strengthened memory–a practice supported by modern research. The name “rosemary” comes from the Latin ros marinus meaning “dew of the sea,” referencing its native coastal habitat where it was said to be nourished by sea spray alone.

In European folklore, rosemary was a symbol of remembrance, fidelity, and love. It was carried at weddings (representing faithful love), worn at funerals (for remembrance of the deceased), and grown near doorways to ward off evil spirits and plague. The famous quote “rosemary for remembrance” from Shakespeare’s Hamlet reflects this deep cultural association.

Christian legend says that rosemary flowers turned from white to blue when the Virgin Mary laid her cloak over a rosemary bush while fleeing to Egypt, and the plant has been called “Mary’s mantle” ever since. In medieval times, rosemary was burned as incense in churches and sick rooms to purify the air–a practice that had actual antimicrobial benefit.

Hungarian Queen Elizabeth is said to have used “Hungary Water,” a rosemary and alcohol preparation, to cure her paralysis and restore her youthful beauty. This became one of the first alcoholic perfumes in Europe (14th century) and was believed to have rejuvenating properties.

In the language of flowers, rosemary means remembrance and fidelity, and sprigs are still traditionally laid on coffins or worn on Anzac Day in Australia and New Zealand as a symbol of remembrance for fallen soldiers.

Additional Information

Varieties: There are numerous cultivars with slightly different growth habits (prostrate, upright), flower colors (blue, pink, white), and hardiness levels. ‘Tuscan Blue’ is particularly aromatic; ‘Prostratus’ is excellent as ground cover; ‘Arp’ is among the most cold-hardy varieties.

Culinary Use: Rosemary is one of the most popular culinary herbs worldwide, particularly in Mediterranean cuisine. It pairs beautifully with roasted meats, potatoes, bread, and olive oil. Regular culinary use provides gentle therapeutic benefits.

Companion Planting: Rosemary repels many garden pests including cabbage moths, bean beetles, and carrot flies. It’s an excellent companion plant for brassicas, beans, and carrots. Its flowers attract beneficial pollinators.

Essential Oil Note:

• Commercial rosemary essential oil comes in several chemotypes depending on growing conditions:
  • Cineole type (highest 1,8-cineole): Best for respiratory and cognitive uses
  • Camphor type (highest camphor): More stimulating, better for muscular pain
  • Verbenone type (highest verbenone): Considered gentler, preferred for skin care Always check which chemotype you’re purchasing for your intended use.

Growing in NZ: Rosemary thrives throughout most of New Zealand, particularly in coastal areas. It’s drought-tolerant once established and handles frosts down to about -10°C when mature. It makes an excellent low-maintenance hedge or border plant.

Sources

Moss, M., & Oliver, L. (2012). Plasma 1,8-cineole correlates with cognitive performance following exposure to rosemary essential oil aroma. Therapeutic Advances in Psychopharmacology, 2(3), 103–113. https://doi.org/10.1177/2045125312436573

Moss, M., Cook, J., Wesnes, K., & Duckett, P. (2003). Aromas of rosemary and lavender essential oils differentially affect cognition and mood in healthy adults. International Journal of Neuroscience, 113(1), 15–38. https://doi.org/10.1080/00207450390161903

Pengelly, A., Snow, J., Mills, S. Y., Scholey, A., Wesnes, K., & Butler, L. R. (2012). Short-term study on the effects of rosemary on cognitive function in an elderly population. Journal of Medicinal Food, 15(1), 10–17. https://doi.org/10.1089/jmf.2011.0005

Nieto, G., Ros, G., & Castillo, J. (2018). Antioxidant and antimicrobial properties of rosemary (Rosmarinus officinalis, L.): A review. Medicines, 5(3), 98. https://doi.org/10.3390/medicines5030098

Satoh, T., Kosaka, K., Itoh, K., Kobayashi, A., Yamamoto, M., Shimojo, Y., … & Lipton, S. A. (2008). Carnosic acid, a catechol-type electrophilic compound, protects neurons both in vitro and in vivo through activation of the Keap1/Nrf2 pathway. Journal of Neurochemistry, 104(4), 1116–1131. https://doi.org/10.1111/j.1471-4159.2007.05039.x

Borrás-Linares, I., Stojanović, Z., Quirantes-Piné, R., Arráez-Román, D., Švarc-Gajić, J., Fernández-Gutiérrez, A., & Segura-Carretero, A. (2014). Rosmarinus officinalis leaves as a natural source of bioactive compounds. International Journal of Molecular Sciences, 15(11), 20585–20606. https://doi.org/10.3390/ijms151120585

Bone, K., & Mills, S. (2013). Principles and practice of phytotherapy: Modern herbal medicine (2nd ed.). Churchill Livingstone.

Chevallier, A. (1996). The encyclopedia of medicinal plants. DK Publishing.

Grieve, M. (1931). A modern herbal. Jonathan Cape.

Hoffmann, D. (2003). Medical herbalism: The science and practice of herbal medicine. Healing Arts Press.

Mills, S., & Bone, K. (2005). The essential guide to herbal safety. Churchill Livingstone.

Barnes, J., Anderson, L. A., & Phillipson, J. D. (2007). Herbal medicines (3rd ed.). Pharmaceutical Press.

Blumenthal, M. (Ed.). (2003). The ABC clinical guide to herbs. American Botanical Council.

Edwards, S. E., da Costa Rocha, I., Williamson, E. M., & Heinrich, M. (2015). Phytopharmacy: An evidence-based guide to herbal medicinal products. John Wiley & Sons.

van Wyk, B.-E., & Wink, M. (2017). Medicinal plants of the world (2nd ed.). CABI.

Williamson, E. M., Driver, S., & Baxter, K. (Eds.). (2013). Stockley’s herbal medicines interactions. Pharmaceutical Press.

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