Practical
Plants

Pachyrhizus tuberosus

Jicama

a perennial woody member of the Pachyrhizus genus in the family Leguminosae.

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Taxonomy and growth

Life cycle
perennial
Woodiness
woody
Height
6 m
Fertility
Insects
Flower type
hermaphrodite
Pollinators
Insects

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

The seed might be poisonous[1].

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Root - raw or cooked[2]. Thirst quenching and nutritious[1]. A source of starch, it is used in custards and puddings[4][5]. Individual roots can weigh up to 20kg[3]. Young seed pods - cooked and used like French beans[1][4][5]. The pods must be thoroughly cooked in order to remove the toxic principle rotenone[3].

Plant part
Root
Plant part
Seedpod

Material uses

This section contains historical Plants For A Future notes marked noncommercial.

The plant contains rotenone, the active ingredient in the insecticide 'derris', and it has the potential to be used as an insecticide[3]. Derris is a relatively safe insecticide in that it does not affect warm-blooded animals and also breaks down into harmless substances with 24 hours of being used. It does, however, kill some beneficial insects and is also toxic to fish and amphibians[K].

Product or use
Insecticide

Ecology and functions

Ecosystem niche
Climber

Nitrogen fixer

Environment

Range
S. America - Peru.
Habitat
Growing into trees and shrubs, often in disturbed areas and usually near the coast, from sea level to 500 metres.
Light
full sun
Shade tolerance
no shade
Water
moderate
Hardiness
Zone 10+
Soil textures
sandy, loamy
Soil pH
acid, neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Pre-soak the seed for 12 hours in warm water and then sow in early spring in a warm greenhouse. Germination should take place within 2 weeks. As soon as they are large enough to handle, prick out the seedlings into individual pots of rich soil and grow them on fast. Plant them out after the last expected frosts. Give the plants some protection, such as a cloche, until they are growing away well. Division of the root tubers in the autumn. Store the roots in a cool but frost-free place over the winter, planting them into pots in the greenhouse in early spring and planting them out after the last expected frosts. Give the plants some protection, such as a cloche, until they are growing away well. Cuttings.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Prefers a light rich sandy soil[1]. Often cultivated for its edible root and seedpods in tropical areas[4], this plant is not hardy outdoors in Britain and requires greenhouse treatment[3] but could possibly be grown as a half-hardy annual. When grown for its root the flowers should be removed[1]. Plants are unlikely to form a tuber when grown in Britain due to their photoperiodic requirements[3]. This means that the plants require between 11 - 13 hours of daylight hours per day in order to initiate tuber production[K]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[3].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2↩3↩4↩5

  2. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

    ↩

  3. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5↩6

  4. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩1↩2↩3

  5. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩1↩2

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