Java waterdropwort (Oenanthe javanica)

Oenanthe javanica
(Java waterdropwort)
Plants
Exotic

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Impacts

Oenanthe javanica (Blume) DC.

Common name: Java waterdropwort

Synonyms and Other Names: Oenanthe stolonifera Wall. ex DC., Oenanthe javanica ssp. javanica (Blume) DC., Oenanthe javanica ssp. stolonifera (Wall. ex DC.) Murata (ITIS 2022); Java water dropwort, water celery, water dropwort, seri, Japanese parsley, Chinese celery, sui-kan, pak chi lawm, shelum, and damoe

Taxonomy: available through www.itis.gov

Identification: Oenanthe javanica is an herbaceous perennial which grows up to nearly 2 meters and occasionally branches. Its stems are light green and hollow, with vertical veins (Illinois Wildflowers 2022) Its leaflets possess coarse toothlets and are sometimes slightly lobed and crinkled (iNaturalist 2022). Yatskievych and Raveill (2001) listed the following details: “Leaves are alternate and sometimes also basal, with blades 3-20 cm long in ovate to triangular ovate in outline. Flowers number 5 to numerous in each umbellet with pedicels 1-5 mm long. Flowers possess 5 sepals with minute triangular teeth and 5 white petals that are obovate, appearing shallowly notched apically but narrowed abruptly to a slender pointed at the tip.”

Size: About 2 m (Stephens 2018)

Native Range: The species is native to East Asia.

Alaska

Hawaii

Puerto Rico &
Virgin Islands

Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: The species has been introduced to Italy, where it is commercially cultivated in Italy (iNaturalist 2022). It has been introduced to Hawaii, Illinois, Minnesota, Missouri, Ohio, and Wisconsin (Yatskievych and Raveill 2001, Invasive Plant Atlas 2014, Stephens 2018, USDA 2022, Seely 2011). It has also naturalized in India and Queensland, Australia (iNaturalist 2022).

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Oenanthe javanica are found here.

State	First Observed	Last Observed	Total HUCs with observations†	HUCs with observations†
DC	1999	1999	1	Middle Potomac-Anacostia-Occoquan
GA	2007	2009	1	Oostanaula
IL	1998	2013	4	Chicago; Des Plaines; Embarras; Upper Kaskaskia
MD	2005	2005	1	Middle Potomac-Anacostia-Occoquan
MN	2016	2022	2	Middle Minnesota; Twin Cities
MO	1996	2000	1	Blackwater
NH	2015	2015	1	Contoocook River
NJ	2019	2020	3	Middle Delaware-Musconetcong; Raritan; Sandy Hook-Staten Island
OH	2018	2018	1	Little Miami
VA	2003	2013	2	Middle Potomac-Anacostia-Occoquan; Middle Potomac-Catoctin
WI	2001	2016	3	Middle Rock; Milwaukee; Sugar

Table last updated 1/12/2026

† Populations may not be currently present.

Ecology: Oenanthe javanica is a perennial herbaceous plant that inhabits a variety of locales with saturated soils. This ranges from soggy meadows and muddy stream banks to marshes and lake shores (Illinois Wildflowers 2022). It possesses no discernable preference for substrate type or inherent nutrient availability and will also grow without rooting itself to substrate(Chang et al. 2012, Barco and Borin 2020). It will tolerate a variety of light availability conditions but seems to prefer semi-shaded habitat (Misako et al. 1987). The pH preference of the species skews slightly acidic but it will tolerate a range of pH levels from about 5-8 (Choi et al. 2012, Plants for a future 2022). Additionally, the species is known to buffer soil pH, ensuring that pH levels remain within a narrow range around neutral (Xin et al. 2012). Finally, the species can grow in a range of climatic conditions, as its native habitats include both tropical and temperate regions and it has also been introduced to colder climates in areas like Minnesota and Wisconsin, where the species has been observed overwintering (iNaturalist 2022, Seely 2011, Invasive Plant Atlas 2018).

The species can reproduce via sexual reproduction but more commonly reproduces via vegetative fragmentation. Broken fragments of the plant disperse via water currents and will take root downstream, allowing the species to spread quickly (Bowen 2020).

Means of Introduction: There are several means of introductions for O. javanica. Viable fragments of the species can disperse on water currents or get caught on boat trailers and other water gear (Bowen 2020). The species is also available for sale in specialty supermarkets and in some cases cultivated for commercial sale or its phytoremediation potential, creating the possibility that viable individuals may escape from personal gardens of individuals (Morton and Snyder 1978, Hargis 1998). Additionally, the species is available for purchase and has uses in the aquarium trade, increasing the potential that individual plants will escape outdoor water gardens or owners will intentionally release plants.

Impact of Introduction:

Summary of species impacts derived from literature review. Click on an icon to find out more...

Ecological Human Health Other

Oenanthe javanica is susceptible to sclerotinia rot caused by Sclerotinia sclerotiorum which it can pass from host to host (Kwon et al. 2003). The species has also been identified as a second intermediate host of fascioliasis causing species (aka liver flukes), which primarily impacts ungulates but can infect humans as well (Choi et al. 2015). The species has been found to have allelopathic effects on strains of Microcystis spp. (Zhao et al. 2013, Zhang et al 2015). Although literature does not explicitly state that the species will outcompete native species, it has been noted as a dominant macorphyte in India and formed a monoculture in a Wisconsin drainage ditch (Seely 2011, Devi and Singh 2016). The species also inhibited the growth of two Microcystis spp., demonstrating its allelopathic potential (Zhang et al. 2015). Furthermore, the species is likely to alter the hydrology of small streams when it does form dense mats. This may alter stream flow, disturb the air-to-water interface and reduce dissolved oxygen levels, and alter predator-prey interactions.

Oenanthe javanica is sold commercially through specialty supermarkets and aquarium stores. The species is also a carrier for several harmful species of bacteria such as Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus (Kim et al. 2014). This creates the potential for humans to contract various illnesses associated with the aforementioned species. This species is also used in the phytoremediation of wastewater and heavy metals. However, if individual plants which have bioaccumulated heavy metals aren’t removed from the ecosystem, those metals may be released back into the environment when the older roots and shoots decay (Zhou and Wang 2010).

Environmental engineers frequently include O. javanica in floating wetland and other natural phytoremediation systems due to its ability to bioaccumulate phosphorus and nitrogen while lowering levels of chemical oxygen demand (Chen et al. 2017, Du et al. 2018, Du et al. 2020, Gao et al. 2020, Sun et al. 2021, Gao et al. 2022). The species will also bioaccumulate various heavy metals, such as cadmium, copper, lead, and zinc but some studies suggest that bioaccumulating these heavy metals negatively impact the growth of O. javanica (Deng et al. 2006, 2009, Dong et al. 2016, Zanin et al. 2018, Liu et al. 2020).

The species is also sold in specialty supermarkets and aquarium stores, thus contributing to local economies.

The species also possesses significant research value as scientists have begun to study O. javanica, which has a long history of use as a medicinal herb. Traditionally used to treat inflammation and fevers, recent studies have demonstrated the potential for O. javanica extracts to be used in treatments for Parkinson’s, UVB ray exposure, tetrodotoxin poisoning, and various chronic health conditions (Kim et al. 2009, Kim et al. 2013, Ku et al. 2013, Ku et al. 2013, Chan et al. 2017, Her et al. 2019, Jang et al. 2019, Gam et al. 2022).

Ecologically, the species is a preferred plant for the oviposition of Dytiscus sharpi eggs and may have beneficial effects for native diving beetles (Inoda 2011).

References: (click for full references)

Barco, A. and M. Borin. 2020. Ornamental plants for floating treatment wetlands: Preliminary results. Italian Journal of Agronomy 15(2):109-120. https://www.agronomy.it/index.php/agro/article/download/1602/1170.

BONAP's North American Plant Atlas. 2014.
http://bonap.net/MapGallery/County/Oenanthe%20javanica.png. Accessed on 08/02/2022.

Bowen, R. 2020. Lookout for These Emerging Invasive Plants. https://www.dcnr.pa.gov/GoodNatured/pages/Article.aspx?post=117. Accessed on 08/02/2022.

Chan, E. W. C., S. K. Wong, and H. T. Chan. 2017. Ulam Herbs of Oenanthe javanica and Cosmos caudatus: an overview on their Medicinal Properties. Journal of Natural Remedies 16(4):137. https://app.dimensions.ai/details/publication/pub.1090229308.

Chang, R Y., R. Q. Wang, Y. R. Zhang and J. Liu. 2012. Effects of N:P ratio and nutrient level on the competition between invasive Alternanthera philoxeroides and native Oenanthe javanica. Pages 337-342 in Trans Tech Publications Ltd. Wuhan, China.

Chen, P.Z., T. Z. Ren, X. Q. Zheng, Y. M. Liu, W. M. Cheng and J. Sun. 2017. Spatial Distribution Characteristics of Microorganisms in Constructed Wetland System with New Matrix and Its Effect on Sewage Purification. Environmental Engineering Science 34(11):828-834. https://www.liebertpub.com/doi/10.1089/ees.2016.0250.

Choi, J., M. C. Maniquiz, J. H. Kang, K. Lim and L. H. Kim. 2012. Seasonal biomass changes at a newly constructed wetland in agricultural area. Desalination and Water Treatment 38(1-3):337-343. https://www.tandfonline.com/doi/pdf/10.1080/19443994.2012.664399.

Choi, I.W., H. Y. Kim, J. H. Quan, J. G. Ryu, R. Sun and Y. H. Lee. 2015. Monitoring of Fasciola Species Contamination in Water Dropwort by COX1 Mitochondrial and ITS-2 rDNA Sequencing Analysis. Korean Journal of Parasitology 53(5):641-645. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4635834/pdf/kjp-53-5-641.pdf.

Deng, H., Z. H. Ye, and M. H. Wong. 2006. Lead and zinc accumulation and tolerance in populations of six wetland plants. Environmental Pollution 141(1):69-80. https://www.sciencedirect.com/science/article/pii/S0269749105004197.

Deng, H., Z. H. Ye, and M. H. Wong. 2009. Lead, zinc and iron (Fe2+) tolerances in wetland plants and relation to root anatomy and spatial pattern of ROL. Environmental and Experimental Botany 65(2-3):353-362. https://www.sciencedirect.com/science/article/pii/S0098847208001329?via%3Dihub.

Devi, M.H. and P.K. Singh. 2016. Diversity pattern of habitats of Macrophytes in Keibul Lamjao National Park (KLNP), a floating mat (Phumdi) environment of Loktak Lake, Manipur, India. IRA - International Journal of Applied Sciences 3(2):157-179. https://app.dimensions.ai/details/publication/pub.1068830042.

Dong, Y., S. Zhou, M. Ji, J. Xu, G. Zhan, and J. Liu. 2016. Study on the Causes of Pb Pollution in Inarticulate Water Dropwort Cultivated in Deep Water. International Journal of Ecology 5(2):17-23. https://lens.org/057-893-410-920-360.

Du, Y., K. X. Pan, C. C. Yu, B. Luo, W. L. Gu, H. Y. Sun, Y. Min, D. Liu, Y. Geng, W.Han, S.X. Chang, Y. Liu, D. Li, Y. Ge, and J. Chang. 2018. Plant diversity decreases net global warming potential integrating multiple functions in microcosms of constructed wetlands. Journal of Cleaner Production 184:718-726. https://www.sciencedirect.com/science/article/pii/S095965261830605X?via%3Dihub.

Du, Y., B. Luo, W. Han, Y. Duan, C. Yu, M. Wang, Y. Ge1, and J. Chang. 2020. Increasing plant diversity offsets the influence of coarse sand on ecosystem services in microcosms of constructed wetlands. Environmental Science and Pollution Research 27(27):34398-34411. https://link.springer.com/article/10.1007/s11356-020-09592-5.

Gam, D. H., J. H. Park, S. H. Kim, M. H. Kang, S. B. Kim, and J. W. Kim. 2022. Production of Bioactive Substances to Alleviates Hangover and Ethanol-Induced Liver Damage through Fermentation of Oenanthe javanica Using Lactiplantibacillus plantarum. Molecules 27(4):14. https://www-mdpi-com.proxy.lib.umich.edu/1420-3049/27/4/1175.

Gao, J., L. Yang, R. Zhong, Y. Chen, J. S. Zhang, J. L. Gao, M. Cai, and J. Zhang. 2020. Comparison of nitrogen and phosphorus removal efficiency between two types of baffled vertical flow constructed wetlands planted with Oenanthe Javanica. Water and Science Technology 81(9):2023-2032. https://iwaponline.com/wst/article/81/9/2023/74553/Comparison-of-nitrogen-and-phosphorus-removal.

Gao, J., Q. Li, J. Zhang, S. Wang, B. Song, and Z. Huang. 2022. Purification of Micro-Polluted Lake Water by Biofortification of Vertical Subsurface Flow Constructed Wetlands in Low-Temperature Season. Water 14(6):896. https://app.dimensions.ai/details/publication/pub.1146244575.

Hargis, F. 1998. Use of the exotic plant Oenanthe javanica in plant/rock filters for on-site wastewater disposal. Journal of Environmental Health 60(10):18-25. https://www-proquest-com.proxy.lib.umich.edu/intermediateredirectforezproxy.

Her, Y., B. N. Shin, Y. L. Lee, J. H. Park, D. W. Kim, K. S. Kim, H. Kim, M. Song, J. D. Kim, M. H.Won, and J. H. Ahn. 2019. Oenanthe javanica Extract Protects Mouse Skin from UVB Radiation via Attenuating Collagen Disruption and Inflammation. International Journal of Molecular Sciences 20(6):12. https://www-mdpi-com.proxy.lib.umich.edu/1422-0067/20/6/1435.

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Inoda, T. 2011. Preference of oviposition plant and hatchability of the diving beetle, Dytiscus sharpi (Coleoptera: Dytiscidae) in the laboratory. Entomological Science 14(1):13-19. https://onlinelibrary-wiley-com.proxy.lib.umich.edu/doi/full/10.1111/j.1479-8298.2010.00407.x?casa_token=zQM7qRWl-qgAAAAA%3AsUYfxe9dnvcxLhkHPt_4hkWTbKmRbKqQg4MsL_cSjXrjb0OeWuqIT0O0HK40x77H5IclmluibNAc75Q.

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Jang, A. J., C. H. Kim, and J. S. Lee. 2019. Free Amino Acid in Dropwort (Oenanthe javanica) Extract and it’s Effect to the Survival Time of Mice Poisoned with Puffer Fish Toxin. Fisheries and Maritime Education Research 31(4):1114-1124. https://app.dimensions.ai/details/publication/pub.1120732048.

Kim, J.Y., K. H. Kim, Y. J. Lee, S. H. Lee, J. C. Park, and D. H. Nam. 2009. Oenanthe javanica extract accelerates ethanol metabolism in ethanol-treated animals. BMB Reports 42(8):482-485. http://koreascience.or.kr:80/article/JAKO200910103465626.pdf.

Kim, T. H., S. K. Ku, and J. S. Bae. 2013. Persicarin is anti-inflammatory mediator against HMGB1-induced inflammatory responses in HUVECs and in CLP-induced sepsis mice. Journal of Cellular Physiology 228(4):696-703. https://onlinelibrary.wiley.com/doi/10.1002/jcp.24214.

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Ku, S. K., T. H. Kim, and J. S. Bae. 2013. Anticoagulant activities of persicarin and isorhamnetin. Vascular Pharmacology 58(4):272-279. https://www.sciencedirect.com/science/article/pii/S1537189113000062?via%3Dihub.

Ku, S. K., T. H. Kim, S. Lee, S. M. Kim, and J. S. Bae. 2013. Antithrombotic and profibrinolytic activities of isorhamnetin-3-O-galactoside and hyperoside. Food and Chemical Toxicology 53:197-204. https://www.sciencedirect.com/science/article/pii/S0278691512008472?via%3Dihub.

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Zhang, S.H., L. Guo, J. Y. Cao, and J. J. Chang. 2015. Allelopathic Activities of Three Emergent Macrophytes on Several Monospecific Cyanobacterial Species and Natural Phytoplankton Assemblages. Polish Journal of Environmental Studies 24(1):397-402. http://www.pjoes.com/pdf-50798-23347?filename=Allelopathic Activities.pdf.

Zhao, J. X. M. He, P. S. Sun, and S. H. Zhang. 2013. Different Sensitivities of Unicellular and Colonial Microcystis Strains (Cyanophyceae) to Six Emergent Macrophytes. Polish Journal of Environmental Studies 22(5):1539-1546. http://www.pjoes.com/Different-Sensitivities-of-Unicellular-and-Colonial-r-nMicrocystis-Strains-Cyanophyceae,89120,0,2.html.

Zhou, X.H. and G.X. Wang. 2010. Nutrient concentration variations during Oenanthe javanica growth and decay in the ecological floating bed system. Journal of Environmental Sciences 22(11):1710-1717. https://www.sciencedirect.com/science/article/pii/S1001074209603107?via%3Dihub.

Author: Pfingsten, I.A., D. Rose

Revision Date: 1/5/2026

Citation Information:
Pfingsten, I.A., D. Rose, 2026, Oenanthe javanica (Blume) DC.: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=3046, Revision Date: 1/5/2026, Access Date: 1/12/2026

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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