Water spangles (Salvinia minima)

Also known as: small salvinia

Water spangles is a free-floating fern that can completely cover waterways. It outcompetes native plants and reduces habitat for fish and other aquatic animals.

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How does this weed affect you?

Water spangles forms dense mats that can:

• smother the surface of the water and outcompete native water plants 
• reduce food and habitat for fish and other aquatic animals
• reduce water quality, including lowering oxygen levels.

What does it look like?

Water spangles is a fast-growing, free-floating water fern. 

Leaves (fronds) are:

• dark green 
• round to oval
• heart shaped or round at the base
• sometimes notched at the tip 
• 1-1.5 cm long
• covered in waxy hairs on the upper surface (the hairs are not joined at the tip)
• grow in opposite pairs.

Stems are:

• green
• covered with fine hairs
• slender up to 6 cm long
• submerged
• branched with nodes.  

Roots:

Water spangles have leaves that look and act like roots. They are:

• hairy and trailing from stem nodes
• up to 25 cm long

Spore sacs are on stalks among the root-like filaments, but they do not produce spores in Australia.

Where is it found?

In NSW, water spangles plants have been found in ponds and aquariums. Naturalised plants have not yet been found in NSW, however if released into waterways they could spread quickly.

Water spangles plants are native to Brazil, southern Mexico and northern Argentina.

What type of environment does it grow in?

Water spangles can grow in tropical or warm temperate climates. Plants grow in still or slow-moving water and prefer shallow water.  

Maps and records

• Recorded presence of Water spangles during property inspections (Map: Biosecurity Information System - Weeds, 2017-2026)
  These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.
  
  

How does it spread?

By plant parts

Water spangles can produce by plant fragments. Currently it is not known to be growing in NSW. Once in a waterway if could be spread by:

• attaching to boats, trailers and vehicles
• human activities such as keeping it in fishponds or aquaria and inappropriate disposal of the plant 
• attaching to animals such as water birds, turtles or cattle
• moving water, especially floods
• wind.

 

References

Madeira, P. T., Jacono, C. C., Tipping, P., Van, T. K., & Center, T. D. (2003). A genetic survey of Salvinia minima in the southern United States. Aquatic Botany, 76(2), 127-139.

Mikulyuk, A. & Nault, M. (2008). CABI Compendium datasheet: Salvina minima. Retrieved 15 November 2024 from: https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.107785

Tipping, P. W., Martin, M. R., Bauer, L., Pierce, R. M., & Center, T. D. (2012). Ecology of common salvinia, Salvinia minima Baker, in southern Florida. Aquatic botany, 102, 23-27.

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Control

Successful weed control relies on follow up after the initial efforts. This means looking for and killing regrowth or new plants. Using a combination of control methods is usually more successful.

Prevention

To reduce the risk of introducing water spangles into waterways, never dump unwanted water plants. 

Physical removal

Remove all plant parts to prevent rapid re-growth. Contact your local council for information about how to dispose of water spangles. 

Herbicide options

Contact your local council weeds officer for control advice for Water spangles (Salvinia minima).

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Biosecurity duty

The content provided here is for information purposes only and is taken from the NSW 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.
Hunter	Regional Recommended Measure* (for Regional Priority - Containment) Entire Hunter Local Land Services region: Land managers should mitigate the risk of the plant being introduced to their land. Exclusion zone: Notify local control authority if found. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Core infestation: Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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Reviewed 2024