PFAF Books ** Please visit the shop to view our books in paperback and digital formats. We have books on Forest/Woodland Gardening, Edible Plants, Edible Trees and a French translation of Edible Plants. All proceeds from the shop go towards the projects of the charity, Plants For A Future. more >>

Search Page Content
   Bookmark and Share
    By donating to PFAF, you can help support and expand our activities
    Plant Suppliers: Click here for a List

Dioscorea japonica - Thunb.                
Common Name Glutinous Yam, Japanese yam
Family Dioscoreaceae
Known Hazards Edible species of Dioscorea have opposite leaves whilst poisonous species have alternate leaves[174].
Habitats Wooded foothills[58]. Mixed forests and margins, scrub forests, herb communities, mountain slopes, valleys, along rivers and streams, roadsides; 100 - 1200 metres[266].
Range E. Asia - China, C. and S. Japan.
Edibility Rating  
Medicinal Rating  
Moist Soil Full sun


Physical Characteristics       
Dioscorea japonica is a PERENNIAL CLIMBER. It is in flower from Sep to October. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required)The plant is not self-fertile.

USDA hardiness zone : Coming soon

Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Dioscorea japonica Glutinous Yam, Japanese yam
Dioscorea japonica Glutinous Yam, Japanese yam
Woodland Garden Sunny Edge; Cultivated Beds;
Edible Uses                                         
Edible Parts: Leaves;  Root.
Edible Uses:

Tuber - cooked[174, 177, 179]. A very pleasant mild flavour with a floury texture, the roots can be eaten as a potato substitute[2]. The starch can be used as a binding agent for other foods[183]. Roots contain about 1.9% protein, 20% carbohydrate, 0.1% fat and 1% ash[179]. Leaf tips - cooked[183]. Tubercles - cooked[183].
Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Contraceptive;  Miscellany;  Tonic.

The tubers are prescribed in the treatment of diarrhoea, enteritis, enuresis and spermatorrhoea[218]. They are also dried and cut into shavings then used as a tonic[218]. The roots of most, if not all, members of this genus, contains diosgenin[222, 240]. 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[222].
Other Uses

None known
Cultivation details                                         
We have very little information on this species and do not know if it will be hardy in Britain, though judging by its native range it could succeed outdoors at least in the mildest areas of this country. The following notes are based on the general needs of the genus. Easily grown in a fertile well-drained soil in a sunny position or light shade[200]. Prefers a rich light soil[1]. Plants produce tubercles (small tubers that are formed in the leaf axils of the stems), and can be propagated by this means[K]. A climbing plant that supports itself by twining around the branches of other plants[219]. Dioecious. Male and female plants must be grown if seed is required.
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[175]. 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[37]. Division in the dormant season, never when in growth[1]. 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 a greenhouse or cold frame. Plant out in early summer when in active growth[K].
Plant Suppliers: Click here for a List

      You can download this page as a PDF

Expert comment                                         
Botanical References                                         
Links / References                                         

  [K] Ken Fern Notes from observations, tasting etc at Plants For A Future and on field trips.

[1]F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).
[2]Hedrick. U. P. Sturtevant's Edible Plants of the World.
Lots of entries, quite a lot of information in most entries and references.
[37]Thompson. B. The Gardener's Assistant.
Excellent general but extensive guide to gardening practices in the 19th century. A very good section on fruits and vegetables with many little known species.
[58]Ohwi. G. Flora of Japan. (English translation)
The standard work. Brilliant, but not for the casual reader.
[174]Kariyone. T. Atlas of Medicinal Plants.
A good Japanese herbal.
[175]Bird. R. (Editor) Focus on Plants. Volume 5. (formerly 'Growing from seed')
Very readable magazine with lots of information on propagation. A good article on Corydalis spp.
[177]Kunkel. G. Plants for Human Consumption.
An excellent book for the dedicated. A comprehensive listing of latin names with a brief list of edible parts.
[179]Reid. B. E. Famine Foods of the Chiu-Huang Pen-ts'ao.
A translation of an ancient Chinese book on edible wild foods. Fascinating.
[183]Facciola. S. Cornucopia - A Source Book of Edible Plants.
Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
[200]Huxley. A. The New RHS Dictionary of Gardening. 1992.
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
[218]Duke. J. A. and Ayensu. E. S. Medicinal Plants of China
Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.
[219]Grey-Wilson. C. & Matthews. V. Gardening on Walls
A nice little book about plants for growing against walls and a small section on plants that can grow in walls.
[222]Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America.
A concise book dealing with almost 500 species. A line drawing of each plant is included plus colour photographs of about 100 species. Very good as a field guide, it only gives brief details about the plants medicinal properties.
[240]Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement).
Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
[266] Flora of China
On-line version of the Flora - an excellent resource giving basic info on habitat and some uses.

Readers comment                                         
Chuck E.
link to scanned page of this book which contains the species Jan 20 2012 12:00AM
Internet Archive- Flora of Japan by Jisaburo Ohwi, p.314
QR Code

What's this?

This is a QR code (short for Quick Response) which gives fast-track access to our website pages. QR Codes are barcodes that can be read by mobile phone (smartphone) cameras. This QR Code is unique to this page. All plant pages have their own unique code. For more information about QR Codes click here.

1. Copy and print the QR code to a plant label, poster, book, website, magazines, newspaper etc and even t-shirts.
2. Smartphone users scan the QR Code which automatically takes them to the webpage the QR Code came from.
3. Smartphone users quickly have information on a plant directly for the website on their phone.
Rate This Plant                                         
Please rate this plants for how successful you have found it to be. You will need to be logged in to do this. Our intention is not to create a list of 'popular' plants but rather to highlight plants that may be rare and unusual and that have been found to be useful by website users. This hopefully will encourage more people to use plants that they possibly would not have considered before.
Add a comment/link                                         

If you have important information about this plant that may help other users please add a comment or link below. Only comments or links that are felt to be directly relevant to a plant will be included. If you think a comment/link or information contained on this page is inaccurate or misleading we would welcome your feedback at If you have questions about a plant please use the Forum on this website as we do not have the resources to answer questions ourselves.

* Please note: the comments by website users are not necessarily those held by PFAF and may give misleading or inaccurate information.

Subject : Dioscorea japonica  

Links To add a link to another website with useful info add the details here
Name of Site
URL of Site