Common Name:

General Information

Rumex japonicus is a herbaceous perennial plant growing from a taproot. The erect stems can be 50 - 100cm tall[].
The plant is harvested from the wil for local use as a food and dye. The young shoots are sold in local food markets in Korea[].

Known Hazards

Plants can contain quite high levels of oxalic acid, which is what gives the leaves of many members of this genus an acid-lemon flavour. Perfectly alright in small quantities, the leaves should not be eaten in large amounts since the oxalic acid can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[].

Botanical References

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Range

E. Asia - Russian Far East, China, Japan, Korea.

Habitat

Wet meadows and ditches in lowland all over Japan[]. Field margins, streambanks and wet valleys; at elevations from sea level to 3,400 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.00 m
Pollinators	Wind
Cultivation Status	Wild

Cultivation Details

Species in this genus generally succeed in a variety of soils, but they prefer deep fertile moderately heavy soils that are humus-rich, moisture-retentive and also well-drained, with a position in full-sun or part shade[].
Being wind -pollinated, Rumex species usually hybridize readily, especially with other members of the genus they are more closely related to[].

Edible Uses

Leaves - cooked[, ]. They can be used as a vegetable or added to soups[]. The young shoots are harvested in the spring[]. The leaves can also be dried for later use[].

Seed - cooked[, ]. It is used with rice or ground into a powder for making dumplings[].

Medicinal

The plant is used medicinally[]. No further information is given, though it is likely that the plant's astringency (especially of the root) is particularly valued[].

Other Uses

Although no specific mention has been made for this species, dark green to brown and dark grey dyes can be obtained from the roots of many species in this genus, They do not need a mordant[].

Propagation

Seed - sow spring in situ.
Division in spring.