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Toxic parts

Edible species of Dioscorea have opposite leaves whilst poisonous species have alternate leaves[1].

Edible uses


Tuber - cooked[2][3][4][5]. A floury texture[6] with a very pleasant flavour that is rather like a potato[K]. The tubers can be boiled, baked, fried, mashed, grated and added to soups[7]. They store well and for a long time[6][8] and can also be left in the ground and harvested as required in the winter[K]. This is a top quality root crop, very suitable for use as a staple food[K]. An arrowroot can be extracted from the root[3], though this is not as good at binding other foods as the starch from D. japonica[7]. The root contains about 20% starch. 75% water, 0.1% vitamin B1, 10 - 15 mg% vitamin C[1]. Fruit. A starchy flavour, it is said to be very good for the health[9]. We wonder if this report is referring to the tubercles[K].


Material uses

There are no material uses listed for Dioscorea batatas.

Medicinal uses(Warning!)

The Chinese yam, called Shan Yao in Chinese herbalism, is a sweet soothing herb that stimulates the stomach and spleen and has a tonic effect on the lungs and kidneys[10]. The tuber contains allantoin, a cell-proliferant that speeds the healing process[10]. The root is an ingredient of \"The herb of eight ingredients\", traditionally prescribed in Chinese herbalism to treat hyperthyroidism, nephritis and diabetes[11].

The tuber is anthelmintic, digestive and gently tonic[12][13][14][11]. It is used internally in the treatment of tiredness, weight loss, poor appetite, poor digestion, chronic diarrhoea, asthma, dry coughs, frequent or uncontrollable urination, diabetes and emotional instability[10]. It is applied externally to ulcers, boils and abscesses[14][10]. The tubers are harvested in the autumn and can be used raw or baked[10]. The leaf juice is used to treat snakebites and scorpion stings[14].

The roots of most, if not all, members of this genus, contains diosgenin[15][16]. This is widely used in modern medicine in order to manufacture progesterone and other steroid drugs. These are used as contraceptives and in the treatment of various disorders of the genitary organs as well as in a host of other diseases such as asthma and arthritis[15].


Ecosystem niche/layer

Ecological Functions

Nothing listed.


Nothing listed.


Nothing listed.


Seed - sow March to April in a sunny position in a warm greenhouse and only just cover. It germinates in 1 - 3 weeks at 20°c[17]. Prick out the seedlings as soon as they are large enough to handle and grow on in a greenhouse for their first year. Plant out in late spring as the plant comes into new growth.

Basal stem cuttings in the summer[8]. Division in the dormant season, never when in growth[2]. The plant will often produce a number of shoots, the top 5 - 10 cm of the root below each shoot can be potted up to form a new plant whilst the lower part of the root can be eaten[K].

Tubercles (baby tubers) are formed in the leaf axils. These are harvested in late summer and early autumn when about the size of a pea and coming away easily from the plant. They should be potted up immediately in individual pots in an unheated greenhouse or cold frame, covering them with about 10mm of soil. Protect them from mice etc and keep the soil moist but not wet. They should come into growth in the spring, plant them out in early summer when in active growth[K].

Practical Plants is currently lacking information on propagation instructions of Dioscorea batatas. Help us fill in the blanks! Edit this page to add your knowledge.


An easily grown plant, succeeding in a fertile well-drained soil in a sunny position or light shade[6][8][18], though it is best in full sun[19].

Plants are hardy to at least -18°c[19]. This species of yam is much cultivated in China for its edible root which can be up to 1 metre long[2]. It has a great potential to be a commercial crop in Britain, though a satisfactory method of harvesting the root needs to be found[K]. Plants take 3 - 4 years to reach full maturity[19], though one year roots of well grown plants can weigh more than 500g. There are many cultivated forms with different root shapes in China and Japan[1]. The yam is a climbing plant that supports itself by twining around the branches of other plants[20]. It can be grown successfully into small bushes or, perhaps simpler when being grown as a root crop, it can be grown up a frame in a similar manner to growing runner beans[K]. Plants produce tubercles (small tubers that are formed in the leaf axils of the stems), and can be propagated by this means[K]. The small white flowers have a pleasant scent of cinnamon[20]. There is some confusion over the correct name for this species. One report says that D. batatas is an invalid name that is often erroneously applied to two distinct species D. opposita and D. japonica[14]. The Flora of China accepts D. batatas as a synonym for D. polystachya[21].

Dioecious. Male and female plants must be grown if seed is required.


Problems, pests & diseases

Associations & Interactions

There are no interactions listed for Dioscorea batatas. Do you know of an interaction that should be listed here? edit this page to add it.

Polycultures & Guilds

There are no polycultures listed which include Dioscorea batatas.




None listed.


None listed.

Full Data

This table shows all the data stored for this plant.

Binomial name
Dioscorea batatas
Imported References
Material uses & Functions
Edible uses
None listed.
Material uses
None listed.
Medicinal uses
None listed.
Functions & Nature
Provides forage for
Provides shelter for
Hardiness Zone
Heat Zone
full sun
light shade
Soil PH
Soil Texture
Soil Water Retention
Environmental Tolerances
    Native Climate Zones
    None listed.
    Adapted Climate Zones
    None listed.
    Native Geographical Range
    None listed.
    Native Environment
    None listed.
    Ecosystem Niche
    None listed.
    Root Zone Tendancy
    None listed.
    Deciduous or Evergreen
    Herbaceous or Woody
    Life Cycle
    Growth Rate
    Mature Size
    Flower Colour
    Flower Type


    1. ? Kariyone. T. Atlas of Medicinal Plants. ()
    2. ? F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press (1951-00-00)
    3. ? Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim (1959-00-00)
    4. ? 4.04.1 Usher. G. A Dictionary of Plants Used by Man. Constable ISBN 0094579202 (1974-00-00)
    5. ? 5.05.1 Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing (1976-00-00)
    6. ? Vilmorin. A. The Vegetable Garden. Ten Speed Press ISBN 0-89815-041-8 ()
    7. ? Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications ISBN 0-9628087-0-9 (1990-00-00)
    8. ? Thompson. B. The Gardener's Assistant. Blackie and Son. (1878-00-00)
    9. ? 9.09.1 Larkcom J. Oriental Vegetables John Murray ISBN 0-7195-4781-4 (1991-00-00)
    10. ? Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. ISBN 0-7513-020-31 (1995-00-00)
    11. ? Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London ISBN 9-780751-303148 (1996-00-00)
    12. ? 12.012.1 Brooklyn Botanic Garden Oriental Herbs and Vegetables, Vol 39 No. 2. Brooklyn Botanic Garden (1986-00-00)
    13. ? 13.013.1 ? A Barefoot Doctors Manual. Running Press ISBN 0-914294-92-X ()
    14. ? Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. ISBN 0-917256-20-4 (1985-00-00)
    15. ? Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. ISBN 0395467225 (1990-00-00)
    16. ? 16.016.1 Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement). Council of Scientific and Industrial Research, New Delhi. (1986-00-00)
    17. ? Bird. R. (Editor) Focus on Plants. Volume 5. (formerly 'Growing from seed') Thompson and Morgan. (1991-00-00)
    18. ? 18.018.1 Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press ISBN 0-333-47494-5 (1992-00-00)
    19. ? Natural Food Institute, Wonder Crops. 1987. ()
    20. ? 20.020.1 Grey-Wilson. C. & Matthews. V. Gardening on Walls Collins ISBN 0-00-219220-0 (1983-00-00)
    21. ? 21.021.1 [Flora of China] (1994-00-00)