- Type
- Herbs & Aromatics
- Difficulty
- Easy
- Season
- Summer·Fall
- Sowing
- From seed
Noyagi (Elsholtzia)
Elsholtzia ciliata
Essential oils and phenolic acids, in a herb once used against summer heat
Noyagi is the old Korean name for Elsholtzia ciliata, a mint-family annual. The Donguibogam lists it under vegetables and notes that every household grew it, that people ate it as a green during the hot months, and that it was cut and dried after the flower spikes formed in the ninth and tenth lunar months. The text explains its alternative name, hyangyeo, as coming precisely from the fact that you could treat it as a vegetable. Today it is used more as a herb and a scent than as food, but the cool, sharp smell released when you rub a leaf is unchanged. It grows easily in a pot, and the one-sided autumn flower spike is worth having for its own sake.
Year-Round Calendar
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Where It Grows
- Main producer It is harvested widely from North China to South China under the name xiangru. In China, however, the source plant for xiangru differs by region, splitting between noyagi (Elsholtzia ciliata) and shixiangru (Mosla chinensis).
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Major producer
It is common on hills, in open country and along field margins, and is also grown in fields. The leaves are picked in summer, and in autumn the plant is cut with the seed heads still attached and dried in the shade. Harvest September, October
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- Wild population Under the name naginata-koju, it grows wild in open country and along roadsides throughout the country.
It is native to temperate East Asia, across the Korean Peninsula, China and Japan as well as the Russian Far East and Mongolia, so it cannot be pinned to any one country. In Europe and North America it arrived in the company of people and has naturalised along roadsides, but those are not counted as growing areas. The FAO has no entry for it, so there are no world production figures.
- Optimum
- 18~25℃
- Range
- 10~32℃
- Hardiness
- Not hardy
An annual aromatic herb that grows through the summer and puts up its flower spikes in autumn. Frost kills it, and it carries over from one year to the next as seed. The stronger the sun, the more concentrated its essential oil and the stronger its scent; where water pools the roots rot easily, so waterlogging during the summer rainy season is the greatest hurdle.
In Korea Nationwide
It is common on hills, in open country and along roadsides nationwide. In years when the summer has been hot and the sun strong, the scent is deeper.
How to grow
- Light
- Five hours of direct sun or more. The better the light, the more concentrated the oil and the stronger the scent.
- Soil and depth
- Not fussy as long as it drains. Ordinary potting mix with about 20 percent coarse grit is plenty.
- Spacing
- 20 to 25 cm between plants, one per 20 cm pot.
- Watering
- Water when the surface dries. It resents wet feet and the roots go quickly if water sits. Move pots under cover during the rainy season.
- Feeding
- Nothing beyond a base dressing. Feed it heavily and you get big leaves with a thin scent.
- Harvest
- Pick leaves as needed from June to August. For drying, cut whole plants in October or November, which is what the original text's ninth and tenth lunar months come to after the spikes form, bundle them, and hang them upside down in shade.
What makes the difference. It is an annual, but it self-seeds freely and often comes back on its own. Cut the spikes before the seed sets if you would rather it did not. For the strongest aroma, cut when the flowers are about half open, and always dry in shade. Direct sun drives the oil off and you end up with scentless leaf.
Common problems
- Aphids You will see Dense colonies on shoot tips and flower spikes, with curling leaves What to do Wash them off with water; if it worsens, spray a soy-lecithin oil mix onto the leaf undersides.
- Spider mites You will see Leaves stippled white with fine webbing on the undersides What to do They thrive in dry air, so mist the leaf undersides to raise humidity.
- Root rot You will see Lower leaves yellow and droop and the whole plant collapses What to do The cause is overwatering. Lengthen the interval between waterings and empty the saucer.
This page describes how a crop is grown and used. It does not claim health effects for any food, nor is it intended to prevent or treat disease. Component and study notes are references only and do not mean the same result occurs in people. Consult a medical professional about health concerns.
Health Benefits
What the Donguibogam recorded. The plant appears in the vegetable section of the Donguibogam under the name hyangyu (香薷). It is listed among the materials used in summer, with a note on cutting whole plants after the flower spikes form in the ninth and tenth lunar months and drying them. This is a record from a seventeenth-century medical text, not a modern medical judgement.
Research on the essential oil. Laboratory assays of the antibacterial and antioxidant activity of Elsholtzia essential oil have been reported repeatedly. Whether anything comparable happens when a person eats or drinks it has not been shown.
Nutrition
- Essential oil (The aromatic fraction of leaf and flower spike) — The cool scent released when the leaves are rubbed
- Elsholtzia ketone and naginata ketone (The main constituents of the oil) — The sharp scent particular to this plant
- Phenolic acids such as rosmarinic acid (Leaf constituents) — Common markers in antioxidant assays
The essential oil is the substance Almost everything of interest in this plant sits in the essential oil held in leaves and flower spikes. Elsholtzia ketone and naginata ketone dominate it, and they are the source of the cool, peppery smell you get on your fingers. The oil is volatile, so long boiling drives it off; add the leaf at the end of cooking, not the beginning.
Rosmarinic acid and related phenolics Like other mint-family plants, it carries phenolic acids such as rosmarinic acid in the leaf. These are the compounds most often used as a marker in antioxidant activity assays. They survive drying reasonably well and are still detectable in dried leaf.
Drying turns it into a different ingredient The original text has the plant cut and dried after the spikes form, so drying was always part of how it was used. Volatile oil drops during drying while everything left behind concentrates. Fresh summer leaf eaten as a green and dried autumn spikes brewed as tea are, in practice, two different materials.
Pairings
○ Summer soups — Drop a few leaves in after the soup comes off the heat and the aroma survives. The Donguibogam's note about eating it during the hot months points the same way. Boil it and there is nothing left to smell.
○ Cucumber, eggplant, other mild summer vegetables — Finely shredded through a dressed summer vegetable, it lifts something that would otherwise read as flat. Use it anywhere you would use perilla leaf or Korean mint. Cucumber · Eggplant
○ Dried leaf tea — One to two grams of dried leaf, three minutes in hot water. Longer and the bitterness comes forward. A little honey rounds the aroma out.
△ Pregnancy and breastfeeding — This is a medicinal plant with a strong essential oil profile, and the safety data for pregnancy and breastfeeding is thin. Eating a little as a vegetable and drinking a strong infusion are two different things. During these periods, do not use it medicinally.
△ Mint-family allergy or oil sensitivity — If mint or perilla has caused you trouble before, treat this plant carefully too. Concentrated essential oil in prolonged skin contact can irritate, so avoid rubbing fresh leaves in your hands for long.
△ Strong infusions, often — Ingredients dense in essential oil can burden the digestive tract when the amount accumulates. Drinking this tea like water is not a good idea. One or two short-brewed cups a day is a reasonable ceiling.
Varieties
- Hyangyu (Seed) — The standard species. The flower spike sets to one side.
- Kkot-hyangyu (Seed) — Denser flower spikes in a deeper purple. Widely planted as an ornamental too.
- Ganeunip-hyangyu (Seed) — Narrower leaves and a stronger scent.
Source: Donguibogam, Vegetable Section (香薷) · Korean Plant Names Index · Rural Development Administration (nongsaro.go.kr)