Common Name: Japanese Sago Palm

General Information

Japanese sago palm is a slow growing cycad, producing a crown of leaves 50 - 150cm long on a stem that is usually quite short. However, older specimens will usually develop a stem about 200 mm across, and eventually up to 6 metres tall - though this is likely to be a VERY old plant several centuries of age[]. Usually single stemmed, although it is not uncommon for a plant to produce occasional offshoots which can be removed and potted up[, ].
The plant is harvested from the wild for local use as a food and medicine, it is also often grown as an ornamental in gardens[].
Plants occur primarily on steep to precipitous stony sites, but previously they occurred on flatter land which has since been cleared. There has been massive seed collecting from natural habitats and leaves are exported in large numbers for decorative purposes. Current populations are considered to be stable and so the plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2011)[].

Known Hazards

The plants contain alkaloids of carcinogens and also an amino-acid that causes chronic nervous disorders[]. Regular consumption of the plant leads to severe health problems and death. This toxic principle can be removed if the food is properly prepared but consumption of the plant still cannot be recommended because its use often means the death of the plant and it is becoming rare in the wild.

Botanical References

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Range

E. Asia - China, Japan.

Habitat

Found mainly on the sea shore in S. Japan[]. Thickets on hillsides on islands, sparse forests on mainland at elevations of 100 - 500 metres in E. China[]. Primarily on steep to precipitous stony sites, but previously on flatter land now cleared[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Habit	Evergreen Tree
Height	3.50 m
Growth Rate	Slow
Pollinators	Insects, Wind
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

This species is probably the hardiest cycad, able to tolerate light frosts[]. It can be grown from the warm temperate zone through to the tropics[].
Requires a sunny position[]. Plants are sometimes found in dense shade in the wild[]. Requires a strong loam with sharp sand and good drainage[]. Succeeds in dry soils.
Plants are very slow growing[, ].
This plant is often used as a food source in its native range but recent research has shown that it can cause chronic nervous disorders if it is not treated properly[]. Overall its use is not to be recommended, especially since it is becoming rare in the wild.
The plants produce special upward growing roots where nitrogen is produced in symbiosis with algae[].
Dioecious, male and female plants must be grown if seed is required.

Edible Uses

Seed - raw or cooked[, , ]. They can be dried and ground into a powder then mixed with brown rice and fermented into 'date miso' or 'sotetsu miso'[]. Caution is advised, see the notes above on toxicity.

The heart or pith of the trunk is sliced and eaten baked or powdered. A toxic principal must first be removed[]. A starch can be extracted from this pith and is used for making dumplings[]. It is very sustaining[, ].

Medicinal

The leaves are used in the treatment of cancer and hepatoma[].

The terminal shoot is astringent and diuretic[].

The seed is emmenagogue, expectorant and tonic[]. It is used in the treatment of rheumatism[]. Substances extracted from the seeds are used to inhibit the growth of malignant tumours[].

Other Uses

None known

Propagation

Seed - best sown in containers as soon as it is ripe. Stored seed should be pre-soaked for 24 hours in warm water prior to sowing. The seed should be sown 2cm deep in individual pots, which are then sealed in plastic bags to keep them moist until germination takes place. Germinates in 1 - 3 months at 25°c[].
Division of suckers in the spring[].

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