Spongeplant is a water weed with small, spongy glossy leaves. Plants grow very quickly, forming dense mats over water bodies.
Spongeplant is a fast growing, freshwater weed that:
Spongeplant is a perennial water weed that can be free floating or rooted in mud.
Young leaves have a central disk with red spongy cells on the underside. As the leaves mature they lose the spongy cells and can extend up to 50 cm above the water.
After the female flowers have been pollinated, the flower stalk bends over so that fruit are formed in the mud or underwater.
There are two types of stems.
Spongeplant looks like two other weed species:
Spongeplant has not been found in Australia.
It is native to the south eastern states of the United States of America (USA) .
Spongeplant grows in fresh water and prefers areas where winter temperatures stay above 0°C. It can grow in regions with winter temperatures below 0°C but there are no green parts present over winter. Plants can be free floating or rooted in mud. It tolerates both shade and full sun.
In the USA it grows in lakes, ponds, swamps, wetlands and along the edges of rivers, canals and ditches.
Each fruit can produce more than 200 seeds which are released under the water or in the mud. Seeds sprout under water and then the small seedlings float to the surface where they can then be spread by water currents. Numerous small bristles on the seeds could help them stick to birds, other animals or water craft. Seeds could also be spread in contaminated mud.
Spongeplant spreads within a water body from daughter plants. Spread to new areas can occur when young plants or plant parts are moved by water, birds or attaching to watercraft or equipment.
Cook, C. D. K. (1998). Hydrocharitaceae. In Flowering Plants: Monocotyledons (pp. 234-248). Springer, Berlin, Heidelberg.
Cook, C. D., & Urmi-König, K. (1983). A revision of the genus Limnobium including Hydromystria (Hydrocharitaceae). Aquatic Botany, 17(1), 1-27.
Les, D. H., & Mehrhoff, L. J. (1999). Introduction of nonindigenous aquatic vascular plants in southern New England: a historical perspective. Biological invasions, 1(2), 281-300.
UF/IFAS (2021). Limnobium spongia. Centre for Aquatic and Invasive Plants. Retrieved 13 April 2021 from: https://plants.ifas.ufl.edu/plant-directory/limnobium-spongia/
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.
Check for plants in fish ponds, aquariums, fish tanks, water features, dams and waterways.
Do not dump aquarium plants.
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
Diquat 200 g/L
(Reglone®)
Rate: 5 L of product per megalitre of water
Comments: Apply by injection below the surface or as a surface spray.
Withholding period: Do not use treated water for human consumption, livestock watering or irrigation purposes for 10 days after application. Do not graze or cut sprayed vegetation for stock food for 1 day after application. See label for harvest withholding periods.
Herbicide group: L, Inhibitors of photosynthesis at photosystem I (PSI inhibitors)
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 All species of Limnobium are Prohibited Matter |
Reviewed 2021