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Amorphophallus konjac
Araceae FAMILY

Amorphophallus konjac

Amorphophallus konjac

Edibility
4/5
Medicinal
2/5

Safety & Hazards

We have one report that this plant is very toxic raw, though no more details are given[1]. It belongs to a family where most of the members contain calcium oxalate crystals. This substance is toxic fresh and, if eaten, makes the mouth, tongue and throat feel as if hundreds of small needles are digging in to them. However, calcium oxalate is easily broken down either by thoroughly cooking the plant or by fully drying it and, in either of these states, it is safe to eat the plant. People with a tendency to rheumatism, arthritis, gout, kidney stones and hyperacidity should take especial caution if including this plant in their diet[2].

Cultivation Details

HabitPerennial
Growth—

Plants can tolerate a minimum temperature of 15°c during the growing season, though the optimum range is 20 - 25°c[3]. The plants are not winter hardy outdoors in Britain but are sometimes grown outdoors in this country as part of a sub-tropical bedding display[4]. The best crops are produced on deep, fertile, alluvial soils that are slightly acid[5]. Dislikes heavy clay soils[5]. Plants require some shade, especially when young[5]. In the temperate zone it probably requires a position with at least moderate sun[6]. Members of this genus generally require a moist but well-drained, humus-rich, fertile soil and a position in dappled shade[3]. The plant produces one enormous leaf and one flowering stem annually. When ripe for pollination, the flowers have a foetid smell to attract carrion flies and midges. This smell disappears once the flower has been pollinated[7]. The tuber is harvested in the autumn after top growth has been cut back by frost and it must be kept quite dry and frost-free over winter[4, 8]. It is then potted up in a warm greenhouse in spring ready to be planted out after the last expected frosts[4]. The tubers are planted 15cm deep[4]. Like many species in the family Araceae, this plant has the ability to heat the flowering spadix as the pollen becomes ready for fertilization. This heat greatly increases the strength of the aroma released by the plant, thus attracting more pollinating insects. It can also have the effect of making the insects more active, thus increasing the level of fertilization[3].

Propagation

Seed - best sown in a pot in a warm greenhouse as soon as it is ripe and the pot sealed in a plastic bag to retain moisture. It usually germinates in 1 - 8 months at 24°c[8]. When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least a couple of years. Plant them out in late spring or early summer, after the last expected frosts, and give them some protection such as a cloche until they are growing away strongly. Division of offsets[4]. These are rarely produced[4]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Amorphophallus+konjac>

Pollinators

Flies

References

  1. [1]Chinese Materia Medica. — Stuart. Rev. G. A. · Taipei. Southern Materials Centre · 1911 · ISBN - ↩︎A translation of an ancient Chinese herbal. Fascinating.
  2. [2]Encyclopaedia of Herbs and their Uses. — Bown. D. · Dorling Kindersley, London. · 1995 · ISBN 0-7513-020-31 ↩︎A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.
  3. [3]Aroids: Plants of the Arum Family. — Bown D. · Timber Press; Portland, Oregon. · 2000 · ISBN 0-88192-485-7 ↩︎An excellent treatment of the family Araceae, giving lots of information about the plants, how to grow them, their uses etc. I found it a bit disordered - if you want all the information on a specific species you have to trawl through the whole book.
  4. [4]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  5. [5]Vegetables in the Tropics — Tindall. H. D. · MacMillan, Oxford. · 1983 · ISBN 0-333-24268-8 ↩︎An excellent, in-depth look at the main vegetable crops that can be grown in the Tropics, plus many less well-known plants.
  6. [6]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  7. [7]Scented Flora of the World. — Genders. R. · Robert Hale. London. · 1994 · ISBN 0-7090-5440-8 ↩︎An excellent, comprehensive book on scented plants giving a few other plant uses and brief cultivation details. There are no illustrations.
  8. [8]Growing from Seed. Volume 1. — Rice. G. (Editor) · Thompson and Morgan. · 1987 · ISBN - ↩︎Very readable magazine with lots of information on propagation.
  9. [9]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎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.
  10. [10]Flora of China — Missouri Botanical Garden Press; St. Louis. · 1994 · http://flora.huh.harvard.edu/china/ ↩︎An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
  11. [11]Medicinal Plants of China — Duke. J. A. and Ayensu. E. S. · Reference Publications, Inc. · 1985 · ISBN 0-917256-20-4 ↩︎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.
  12. [PFAF]Plants for a Future — pfaf.org ↩︎