Hydrocotyl is a fast growing water weed with circular or kidney shaped leaves. It forms dense mats over still or slow-flowing freshwater including rivers, wetlands, lakes and dams.
Hydrocotyl forms dense mats that:
Hydrocotyl is a perennial plant that can grow over water or on the edge of waterways. If on the edge or in shallow water, it has long stolons that creep in the mud. When floating, it forms a tangled mass of roots and leaf stems that can be submerged up to 50 cm into the water. In cold regions it is dormant over winter.
Roots form at the nodes along the long stolons at about 3–10 cm intervals.
Largeleaf pennywort (Hydrocotyle bonariensis) is a similar looking weed. This plant is very common and widespread in the Greater Sydney Region, especially in lawns. Its leaves are circular with shallow lobes and are up to 12 cm wide. The stem joins the leaf in the centre and the underside of the leaf is dull.
There are 17 species of Hydrocotyle in NSW. Most are native and include the following similar looking species:
Hydrocotyl does not currently grow in NSW. There are some infestations near Perth in Western Australia.
Hydrocotyl is native to the Americas, tropical Africa and Asia. It was brought to Australia as an aquarium and ornamental pond plant. Australia's first infestation was in 1983 near Perth. In 1992, a larger infestation covered one-third of the water along a 7 km stretch of the Canning River in WA. It is a serious weed in Europe, Britain, and Ireland and it has naturalised in South Africa.
Hydrocotyl prefers still or slow-moving fresh water in temperate climates. It will grow in rivers, wetlands, lakes and dams especially those with high nutrient levels. It can also grow on the edges of still water bodies.
The fruit produces 2 seeds but only one is usually viable. Water spreads hydrocotyl seeds.
Hydrocotyl can re-grow from very small pieces of stem if they have a node. The fragments can be spread to new locations by flowing water, water birds and human activities such as boating.
Djeddour, D. (2017) CABI Invasive Species Compendium Data sheet: Hydrocotyle ranunculoides (floating pennywort). Retrieved 14 December 2014 from: https://www.cabi.org/isc/datasheet/28068
Hosking, J.R., Sainty, G.R., Jacobs, S.W.L., & Dellow, L.L. (in prep). The Australian WeedBOOK.
Hussner, A., Denys, L., van Valkenburg, J. L., & Warenautoriteit, N. V. E. (2011). Hydrocotyle ranunculoides NOBANIS–Invasive Alien Species Fact Sheet. Retrieved 22 march 2021 from: http://nora.nerc.ac.uk/id/eprint/19956/1/Hydrocotyle_State-of-the-Art.pdf
Queensland Government (2016). Weeds of Australia, Biosecurity Queensland edition Fact sheet: Hydrocotyle ranunculoides L. f. Retrieved 22/03/2021 from https://keyserver.lucidcentral.org/weeds/data/media/Html/hydrocotyle_ranunculoides.htm
Ramírez, C., Romero, M., & Riveros, M. (1979). Habit, habitat, origin and geographical distribution of Chilean vascular hydrophytes. Aquatic Botany, 7, 241-253.
Sainty, G. R., & Jacobs, S. W. (2003). Waterplants in Australia (No. Ed. 4). Sainty and Associates Pty Ltd.
Please do not attempt to treat or dispose of this weed yourself. Report this plant if you see it anywhere in NSW by calling the helpline listed at the top of this page immediately.
NSW DPI will lead an initial response for the treatment and disposal of the plant to stop it from spreading.
See Using herbicides for more information.
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Only products registered for aquatic use)
Rate: One part product to 50 parts water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Only products registered for aquatic use)
Rate: One part product to 9 parts water
Comments: Splatter gun
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
Area | Duty |
---|---|
All of NSW | General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
All of NSW |
Prohibited Matter
A person who deals with prohibited matter or a carrier of prohibited matter is guilty of an offence. A person who becomes aware of or suspects the presence of prohibited matter must immediately notify the Department of Primary Industries |
Reviewed 2021