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Dioscorea japonica - Thunb.

Common Name Glutinous Yam, Japanese yam
Family Dioscoreaceae
USDA hardiness 7-12
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    (4 of 5)
Other Uses    (0 of 5)
Weed Potential No
Medicinal Rating    (2 of 5)
Care (info)
Frost Hardy Moist Soil Full sun
Dioscorea japonica Glutinous Yam, Japanese yam


http://flickr.com/photos/68821308%40N00/1310577941
Dioscorea japonica Glutinous Yam, Japanese yam
http://flickr.com/photos/plj/

 

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Summary


Physical Characteristics

 icon of manicon of flower
Dioscorea japonica is a PERENNIAL CLIMBER growing to 3 m (9ft 10in).
See above for USDA hardiness. It is hardy to UK zone 8. It is in flower from September to October. The species is 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.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

UK Hardiness Map US Hardiness Map

Synonyms

Plant Habitats

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].

References   More on Edible Uses

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].

References   More on Medicinal Uses

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Other Uses

Miscellany

None known

Special Uses

Food Forest

References   More on Other Uses

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. For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. Growth habit is a single or multiple shooting vine from a crown [1-2]. Herbaceous. The root pattern is tuberous with swollen potato-like roots [1-2].

References   Carbon Farming Information and Carbon Sequestration Information

Temperature Converter

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Plants For A Future have a number of books available in paperback and digital form. Book titles include Edible Plants, Edible Perennials, Edible Trees,Edible Shrubs, Woodland Gardening, and Temperate Food Forest Plants. Our new book is Food Forest Plants For Hotter Conditions (Tropical and Sub-Tropical).

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Plant Propagation

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].

Other Names

If available other names are mentioned here

Yamaimo, Japanese Wild Yam, Glutinous Yam, Japanese Cinnamon Vine, mukago, East Asian mountain yam, Japanese mountain yam, French: igname du Japon

Native Range

TEMPERATE ASIA: Anhui Sheng, Fujian Sheng, Guangdong Sheng, Guangxi Zhuangzu Zizhiqu, Guizhou Sheng (east & south), Honshu, Hubei Sheng, Hunan Sheng, Japan, Jiangsu Sheng, Jiangxi Sheng, Korea, Kyushu, Ryukyu Islands, Shikoku, Sichuan Sheng, Taiwan, Zhejiang Sheng,China.

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status

IUCN Red List of Threatened Plants Status :

Related Plants
Latin NameCommon NameHabitHeightHardinessGrowthSoilShadeMoistureEdibleMedicinalOther
Dioscorea alataWater Yam, Purple yam, Greater yam, White yamPerennial Climber15.0 10-12 FLMHSM412
Dioscorea batatasChinese YamPerennial3.0 4-11  LMHSNM553
Dioscorea bulbiferaAerial Yam, Air PotatoPerennial Climber10.0 9-12 FLMHSNM420
Dioscorea cayennensisYellow Yam, Yellow Guinea yamPerennial Climber10.0 10-12 FLMSNM400
Dioscorea deltoideaYamPerennial Climber3.0 -  LMHSNM222
Dioscorea esculentaLesser Yam, Potato Yam, Chinese Yam, Wild YamPerennial Climber3.0 8-12 FLMSNM400
Dioscorea kamoonensis Perennial Climber2.5 -  LMHNM21 
Dioscorea tokoro Perennial Climber0.0 -  LMHNM22 
Dioscorea trifidaCush Cush Yam, Sweet yamPerennial Climber3.0 10-12 FLMHSNM402
Dioscorea villosaWild YamPerennial Climber3.0 5-9  LMHNM24 
Tamus communisBlack BryonyPerennial Climber3.5 4-8 MLMHSNM12 

Growth: S = slow M = medium F = fast. Soil: L = light (sandy) M = medium H = heavy (clay). pH: A = acid N = neutral B = basic (alkaline). Shade: F = full shade S = semi-shade N = no shade. Moisture: D = dry M = Moist We = wet Wa = water.

 

Expert comment

Author

Thunb.

Botanical References

58266

Links / References

For a list of references used on this page please go here

Readers comment

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

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