Dioscorea tokoro
Family: Dioscoreaceae
What it is like
Dioscorea tokoro is a PERENNIAL CLIMBER. 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.
Height (m): 0
Where it is found
Thickets in lowland and foothills all over Japan. Mixed forests, bamboo forests, usually along ravine sides from near sea level to 1,000 metres in China.
E. Asia - China, Japan.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 2
Tuber - cooked. It should be soaked or boiled in lye before use since it is said to be poisonous raw.
Root: includes bulbs, corms, tubers, rhizomes etc.
Medicine
Rating: 2
The roots are antirheumatic, antiseptic, antitussive and contraceptive. They are also used for desensitization. A decoction of the root is used in the treatment of arthritis, rheumatism and prostatitis. It is also a resolvent for blood clots. The roots of most, if not all, members of this genus, contains diosgenin. 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.
Antirheumatic: Treats rheumatism.
Antiseptic: Preventing sepsis, decay or putrefaction, it destroys or arrests the growth of micro-organisms.
Antitussive: Prevents or relieves coughing.
Contraceptive: Prevents fertilization occurring in females.
Miscellany: Various medicinal actions that need more clarification.
Resolvent: Breaks down tumors. This might be placed under antitumor.
Other
Rating:
Miscellany: A rag-bag of items that are difficult to categorise.
How it is grown
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 in many parts 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. Prefers a rich light soil. Plants produce tubercles (small tubers that are formed in the leaf axils of the stems), and can be propagated by this means. A climbing plant that supports itself by twining around the branches of other plants. Dioecious. Male and female plants must be grown if seed is required.
Propagating it: 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. 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. Division in the dormant season, never when in growth. 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 possibly be eaten. 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.
Best place to grow: Woodland Garden Sunny Edge; Cultivated Beds;
Habit: Perennial Climber
Hardiness:
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Moist
Things to keep in mind
Edible species of Dioscorea have opposite leaves whilst poisonous species have alternate leaves. The root of this species is said to be poisonous raw.