- Type
- Tubers & Storage Roots
- Difficulty
- Moderate
- Season
- Spring·Fall
- Sowing
- From spawn or seed tuber
Gastrodia
Gastrodia elata
Gastrodin and 4-hydroxybenzyl alcohol · a leafless orchid tuber under a red stalk
Gastrodia is the tuber of a leafless perennial orchid. It has no chlorophyll and cannot feed itself, so it lives attached to the mycelium of honey fungus, and at flowering time a bare red stalk rises straight out of the ground with no leaf on it. That sight gave the plant the old name 赤箭, red arrow, and the Donguibogam states plainly that gastrodia is the root of that red arrow. The tubers are long like cucumbers and run in a chain of ten to twenty at one spot. Today they are grown by inoculating oak billets with the fungus and burying them in a field or a wood, and markets and farm-gate stalls sell the crop fresh, dried, juiced or powdered. The fresh tuber carries a distinctive rank smell, so it is usually steamed and dried or pressed for juice, though thin slices also go into a stir-fry or a pot of rice. The Donguibogam records scraping the skin off while the tuber is still moist, blanching it briefly in boiling water and drying it in the sun, and counted the firm, solid ones best.
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Where It Grows
- Main producer It is grown in quantity in Dafang in Guizhou, in southern Shaanxi, and in the mountains of Hubei. These areas supply most of the volume traded worldwide.
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Major producer
In inland mountain districts including Muju in North Jeolla, it is grown on oak logs that have been inoculated with the fungus. Harvest October, November
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- Wild population It grows wild in the forests of Honshu and Hokkaido, and cultivation there is small in scale.
It is a saprophytic orchid found across the mountain belt that runs from the temperate forests of East Asia to the eastern Himalaya. Having no chlorophyll, it lives attached to the mycelium of the honey fungus group (Armillaria), so it will not come up without oak logs that have been inoculated with the fungus. As a cultivation method using the fungus took hold in China from the 1970s onward, a crop that had been dug out of the mountains became a field crop.
- Optimum
- 20~25℃
- Range
- 10~28℃
- Hardiness
- Hardy
Because the crop grows underground, soil temperature and soil moisture decide the outcome more than air temperature does. Tubers set best at soil temperatures of 20–25℃, and growth stops below 15℃ or above 28℃. The tubers overwinter — pass the winter — in the ground, and where water collects, the oak logs buried alongside them are the first thing to rot.
Harvested 1–2 years after planting. In spring, oak logs inoculated with the fungus are buried together with seed tubers, and the crop is dug in autumn one or two years later. The month of burying and the month of digging often fall in different years.
In Korea Mountain areas
Inland mountain country with cool summers and plenty of oak suits it best. Muju in North Jeolla and the mountain areas of North Gyeongsang and Gangwon are the known districts.
How to grow
- Light
- Woodland shade or a shaded bed. It grows underground, so soil temperature and moisture matter more than light
- Soil and depth
- Free-draining sandy loam with oak billets buried alongside. Soil alone produces nothing
- Spacing
- Lay the oak billets in rows and set the seed tubers between them. Keep billet touching billet so the mycelium can cross
- Watering
- After burying, keep it just short of drying out. Standing water rots the billets and softens the tubers with them
- Feeding
- No feeding. The mycelium running through the oak billets takes the place of fertiliser
- Harvest
- Lift in October or November, one or two years after burying. Raise the billets and work the tubers free by hand without damaging them. Use the large ones and keep the small white ones as seed tubers to bury again. The Donguibogam records digging in the second, third, fifth and eighth lunar months
What makes the difference. Scrape the skin off while the lifted tuber is still moist, blanch it briefly in boiling water and dry it. The preparation set down in the Donguibogam is close to the modern processing order
Why this one is harder. It only appears where inoculated oak billets are present, so planting seed alone achieves nothing. It takes a year or two for the mycelium to run and the tubers to set, and with no practical way to check underground in the meantime, the result is unknown until the lift. A balcony will not do; this needs a wood or a strip of field
Common problems
- Competing moulds You will see Green or black mould spreads across the buried billets What to do Honey fungus mycelium is white. Lift out and discard any billet another mould has taken over
- Chafer grubs and soil pests You will see Lifted tubers show holes eaten into them What to do Sift the soil for larvae before burying, and raise the bed so water does not sit
- Rot You will see The tuber softens and smells sour What to do Avoid spots where water sits. Dig out rotted tubers and do not bury again in the same place
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
The old record — cheonma (天麻). The Donguibogam lists the material in the Herb section as 天麻. It gives a neutral nature with a note that some call it cold, a pungent taste with a note that some call it sweet, and no toxicity. It states that gastrodia is the root of the red arrow, 赤箭, and describes the tuber as shaped like a cucumber, running in a chain of ten to twenty at one spot. Roots were dug in the second, third, fifth and eighth lunar months and dried in the sun, and the shoot carried its own name, 定風草. The text directs scraping the skin while the tuber is still moist, blanching it briefly in boiling water and sun-drying it for storage, and counts the firm, solid ones best. This is a historical medical record and differs from modern medical judgment.
Analyses of gastrodin. Phenolic compounds such as gastrodin and 4-hydroxybenzyl alcohol have been isolated from the tuber in repeated analyses. The name gastrodin derives from the genus Gastrodia. These are compositional analyses and have nothing to do with preventing or treating disease.
A plant that lives on a fungus. Ecological research confirms that gastrodia, having no chlorophyll, draws its nutrients from the mycelium of honey fungus in the genus Armillaria. The cultivation method of inoculating oak billets first and burying seed tubers alongside them follows from that.
Nutrition
- Gastrodin (in the tuber) — a phenolic glycoside named after the plant's genus
- 4-hydroxybenzyl alcohol (reported in the tuber) — a phenolic compound discussed alongside gastrodin
- Polysaccharides (the substance of the tuber flesh) — the component that turns the flesh translucent on steaming
A plant without chlorophyll Gastrodia has neither leaves nor chlorophyll and cannot make its own food; it draws nutrients from the mycelium of honey fungus. That is why oak billets go into the ground alongside it. Sowing seed into bare soil produces nothing.
Gastrodin A phenolic glycoside named gastrodin was isolated from the tuber, and the name comes straight from the genus Gastrodia. Phenolic compounds including 4-hydroxybenzyl alcohol are reported alongside it. This entry stays with the compositional record.
The raw smell and processing The fresh tuber carries a distinctive rank smell that many find hard to take raw. Steaming and drying it, or pressing it for juice, reduces it. The Donguibogam likewise directs scraping the skin, blanching briefly and sun-drying, which is not far from how it is processed now.
Choosing one The Donguibogam counted the firm, solid tubers best. For fresh gastrodia, choose ones that do not give under pressure, whose skin is little wrinkled and whose cut surface is evenly white. For dried, prefer a yellowish cast over anything strikingly white or bleached-looking.
Pairings
○ Jujube and ginger — Simmering thin slices of dried gastrodia with jujube and ginger settles the distinctive smell. Drop the heat once it boils and hold it at a gentle simmer, adding the ginger at the end. Ginger · Jujube
○ Pear and honey — juiced — Blending pear in with fresh gastrodia adds sweetness and makes the juice easy to drink. Stir the honey in after blending. Use the juice the day it is made. Asian Pear
○ Sesame oil and salt — sliced and fried — Slice fresh gastrodia thin, fry it briefly in sesame oil and season with salt alone. Long cooking draws water and turns it slack, so work fast over high heat. Slice it thin for rice as well.
△ Digging it in the wild — Wild gastrodia is leafless and visible only during the short spell when the flower stalk rises, and digging it at a wild site may fall foul of the relevant regulations. What is to be eaten comes from a grower. Digging roots on a mountainside is a problem in its own right.
△ Juice, powder and pills taken heavily — Juice, powder and pill forms make the quantity easy to scale up without noticing. If you are taking medication, settle the amount and the timing with your doctor or pharmacist, and during pregnancy or before surgery, avoid making a habit of it. Using a little as food and taking a concentrated form daily are handled differently.
△ Mouldy dried tubers — Dried gastrodia that takes up moisture goes limp and grows mould. A white bloom may be nothing more than compounds surfacing, but anything smelling sour or showing green or black mould is discarded. Keep it sealed somewhere cool and dark, and refrigerate it in summer.
Varieties
- Red-form gastrodia (line) — A line with red tones in the stalk and the tuber
- Green-form gastrodia (line) — A line with green tones
- Dried gastrodia (form) — Steamed and dried. Simmered or milled to a powder
Source: Donguibogam, Herb Section 天麻 · Rural Development Administration (Nongsaro)