There is a lot of confusion over the correct name for this species. Some reports give Oenanthe stolonifera. DC. or Oenanthe stolonifera. Wall as the correct name whilst other reports say that these names are synonyms of Oenanthe javanica. [] says that Oenanthe stolonifera japonica. (Miq.)Maxim. Is a synonym of Oenanthe javanica. The Flora of China treats this as a highly variable single species under the name Oenanthe javanica and recognizes at least one sub-species[].

Common Name: Water Dropwort

General Information

Oenanthe javanica is an erect, perennial plant growing from 10 - 150cm tall. The plant has creeping stolons by which it spreads vigorously, often forming large clumps[].
The plant is harvested from the wild for local use as a food and medicine. It is occasionally cultivated in many regions from the tropics to the warm temperate zone as a food and is sold in local markets. There are some named varieties[].

Known Hazards

Although no specific mention of toxicity has been seen for this species, it belongs to a genus that contains a number of very poisonous plants and so some caution is advised[]. It is said to contain the alleged 'psychotroph' myristicine[].

Botanical References

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Range

E. Asia - Mongolia, China, Japan, Korea, Indian subcontinent, Myanmar, Thailand, Vietnam, Malaysia, Indonesia, Philippines, New Guinea, N. Australia.

Habitat

Ditches, ponds and wet places in lowland areas all over Japan[]. Marshlands, lakeshores, muddy stream banks and shallow water; at elevations from 600 - 3,000 metres in most parts of China[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.00 m
Pollinators	Insects
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Oenanthe javanica is found from the warm temperate zone to the tropics, where it can be found at elevations up to 3,400 metres. It grows best in areas where annual daytime temperatures are within the range 10 - 30°c, but can tolerate 4 - 32°c[]. At least some forms of the plant can tolerate some frost, and the plant is cultivated in warm temperate regions[]. It prefers a mean annual rainfall in the range 2,000 - 3,000mm, but tolerates 1,500 - 3,500mm[].
Requires a wet fertile soil or shallow water and a sunny position[]. Prefers a pH in the range 5.5 - 6.5, tolerating 4.5 - 7[].
Yields of 10 tonnes of root per hectare have been reported in New Guinea[].
There are two main forms of this species, a red form has edible shoots whilst a white form is grown for its medicinal root[]. In Japan this plant and six other herbs are customarily boiled in rice gruel on January 7th[]. The cultivar 'Su Zhou' is medium early and has few fibres plus an excellent taste[].

Edible Uses

Young leaves and stems - raw or cooked[, , , ]. Used as 'namul' in Korea - this is a cooked side dish prepared by steaming or blanching the vegetables, placing them in small serving bowls with sesame oil seasoning and serving them at room temperature[]. The leaves are also used as a seasoning in soups etc[, ]. The flavour is reminiscent of carrots or parsley[]. The young shoots that sprout from the root in winter are best[, ]. A major vegetable in many parts of the Orient, the leaves are a rich source of vitamins and minerals (Analysis available)[].

Root - cooked. Highly esteemed in Japan[], the roots can grow up to 30cm long in water[]. Some caution is advised, see the notes above on toxicity.

Seed is said to be edible[].

Medicinal

The whole plant is depurative, febrifuge and styptic[, ]. A decoction is used in the treatment of epidemic influenza, fever and discomfort, jaundice, haematuria and metrorrhagia[].

The leaves are chewed with wild ginger and traditional ash salt as an antidote to poisoning[].
The leaves are rubbed onto the forehead in order to ease a headache[].

The stem is chewed and swallowed to ease a cough[].

The seed contains 3.5% essential oil. This is effective at large dilutions against pathogenic fungi[].

Agroforestry Uses:

Spreading rapidly by means of its roots, it makes a good ground cover plant for wet situations. The variegated cultivar 'Flamingo' has been especially recommended[].

Other Uses

Spreading rapidly by means of suckers, it makes a good ground cover plant for wet situations. The variegated cultivar 'Flamingo' has been especially recommended[].

Propagation

Seed - sow spring in a cold frame. Germination is erratic[]. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer.
Division in spring[]. Large divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.
Layering[].
Stem tip cuttings[]. Any part of the stem roots easily[].