Oenanthe javanica - Water Dropwort

Family:	Umbelliferae
Habit:	Perennial
Height:	1
Synonyms:	O. stolonifera.
Range:	E. Asia - Japan, Korea to Australia.

Oenanthe javanica (Water Dropwort) is a Perennial which grows to a height of 1m . It has a hardness rating of 10.
Water Dropwort will flower in December to February. The flowers from this plant are hermaphrodite (has both male and female organs) and they are pollinated by Insects

Soil Information

Water Dropwort will grow in light (sandy),medium (loamy),hard (clay) soil. It is not necessary for the soil to be well drained.
The soil prefers the following PH / acid levels :
- pH of less than 6, Acidic soils
- pH between 6 and 8, Neutral soils
- pH greater than 8, Basic soils
Water Dropwort prefers soils

Ideal Planting Locations

Water Dropwort should not be planted in shady areas.

Ditches, ponds and wet places in lowland areas all over Japan[58].

Planting places suited to this plant described below.

• Can be planted in Cultivated Beds
• Can spread to cover ground and will out compete weeds
• Is a pond plant
• A bog garden plant

Cultivation Details

Requires a wet fertile soil or shallow water and a sunny position[200]. This plant is quite possibly not hardy in Britain, [200] gives a hardiness zone of 10, which means that it is not frost tolerant. However [58] says that it grows in all areas of lowland Japan and this should include areas that do experience frosts and snow. Another report says that many forms of this species are not frost-hardy, though some forms have hardy roots[206]. There is also a lot of confusion over the correct name for this species. Some reports give O. stolonifera. DC. or O. stolonifera. Wall as the correct name whilst other reports say that these names are synonyms of O. javanica. [200] says that O. stolonifera japonica. (Miq.)Maxim. is a synonym of O. javanica. It is quite possible that both O. javanica and O. stolonifera are valid names and the uses listed here belong partly to each species. More research is required. This species is occasionally cultivated for its edible root[183] or for its edible leaves according to another report[179], there are some named varieties[183]. There are two main forms of this species, a red form has edible shoots whilst a white form is grown for its medicinal root[178]. In Japan this plant and six other herbs are customarily boiled in rice gruel on January 7th[183]. The cultivar 'Su Zhou' is medium early and has few fibres plus an excellent taste[183].

Edible Uses*

* See disclaimer
Edible Rating: 3/5
Young leaves and stems - raw or cooked[2, 46, 61, 105]. The leaves are also used as a seasoning in soups etc[179, 183]. The flavour is reminiscent of carrots or parsley[206]. The young shoots that sprout from the root in winter are best[116, 206]. A major vegetable in many parts of the Orient, the leaves are a rich source of vitamins and minerals (Analysis available)[218]. Root - cooked. Highly esteemed in Japan[116], the roots can grow up to 30cm long in water[183]. Some caution is advised, see the notes above on toxicity. Seed is said to be edible[183].

• Condiment - the various plants that are used as flavourings, either as herbs, spices or condiments.
• Leaves -
• Root - includes bulbs, corms, tubers, rhizomes etc.
• Seed - includes nuts, cereals, peas and beans.

Medicinal Uses*

* See disclaimer
Medicinal Rating: 2/5
The whole plant is depurative, febrifuge and styptic[147, 178]. A decoction is used in the treatment of epidemic influenza, fever and discomfort, jaundice, haematuria and metrorrhagia[147]. The seed contains 3.5% essential oil. This is effective at large dilutions against pathogenic fungi[218].

• Depurative - Eliminates toxins and purifies the system, especially the blood.
• Febrifuge - Reduces fevers.
• Styptic - An astringent that stops bleeding by contracting the blood vessels.

Propagation

Seed - sow spring in a cold frame. Germination is erratic[206]. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer. Division in spring[206]. 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[200]. Stem tip cuttings[200]. Any part of the stem roots easily[206].

Scented parts of the plants

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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[K]. It is said to contain the alleged 'psychotroph' myristicine[218].

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[200].

• Essential - Essential oils that are used in perfumery, medicines, paint solvents, insect repellents etc.
• Ground cover - Usually low growing plants that can be grown with other plants, especially shrubs and trees, to prevent the growth of weeds.

Cultivars

'Flamingo' - A variegated form with leaves splashed and zoned pale pink, cream and white, it has been especially recommended as a good ground cover plant for wet situations[200].
'Su Zhou' - A medium early cultivar, the root of which has few fibres and an excellent taste[183].

References

Flora of Japan. (English translation)
Ohwi. G.
Author: Ohwi. G.
Rating:
Publisher : The standard work. Brilliant, but not for the casual reader.
Date of Publication : 1965

The New RHS Dictionary of Gardening. 1992.
Huxley. A.
Author: Huxley. A.
Rating:
Publisher : Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
Date of Publication : 1992

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