Water lilies (Nymphaea species)

Also known as: water lily, yellow waterlily

Water lilies are aquatic perennial plants. Several species have escaped cultivation.

Profile

How does this weed affect you?

Water lilies are regarded as an environmental weed in NSW and Qld. Waterlilies have escaped cultivation and have become a weed of freshwater habitats where they displace similar native species and blocks waterways. 

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Control

Herbicide options

See Using herbicides for more information.

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Diquat 20 g/L (Watrol®)
Rate: 4.0 L per 100 L of water
Comments: Apply as an overall spray. Thoroughly wet foliage. Best if clean water is used; higher rate if dense weed or dirty water. Observe withholding period.
Withholding period: 1 day in pasture, 10 days in treated water.
Herbicide group: L, Inhibitors of photosynthesis at photosystem I (PSI inhibitors)
Resistance risk: Moderate

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Diquat 20 g/L (Watrol®)
Rate: 50–100 L/ha
Comments: Apply as an overall spray. Thoroughly wet foliage. Best if clean water is used; higher rate if dense weed or dirty water. Observe withholding period.
Withholding period: 1 day in pasture, 10 days in treated water.
Herbicide group: L, Inhibitors of photosynthesis at photosystem I (PSI inhibitors)
Resistance risk: Moderate

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Diquat 200 g/L (Reglone®)
Rate: 400 mL per 100 L of water
Comments: Add Agral 600 wetter; use clean water for best results. Observe withholding period.
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

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Diquat 200 g/L (Reglone®)
Rate: 5.0–10.0 L/ha
Comments: Add Agral 600 wetter; use clean water for best results. Observe withholding period.
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

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Glyphosate 360 g/L (Only products registered for aquatic use)
Rate: 1 L to 100 L of water
Comments: Re-treat unaffected plants.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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Biosecurity duty

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 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.
Central West	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. This Regional Recommended Measure applies to Nymphaea mexicana (Mexican water lily)
Murray	Regional Recommended Measure* (for Regional Priority - Containment) Land managers should mitigate the risk of new weeds being introduced to their land. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. This Regional Recommended Measure applies to Nymphaea mexicana (Mexican water lily)
North West	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. This Regional Recommended Measure applies to Nymphaea mexicana (Mexican water lily)
Northern Tablelands	Regional Recommended Measure* (for Regional Priority - Containment) Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. This Regional Recommended Measure applies to Nymphaea mexicana (Mexican water lily)
Riverina	Regional Recommended Measure* (for Regional Priority - Containment) The plant should be eradicated from the land and the land kept free of the plant. Land managers should mitigate the risk of new weeds being introduced to their land. The plant should not be bought, sold, grown, carried or released into the environment. This Regional Recommended Measure applies to Nymphaea mexicana (Mexican water lily)
	*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 2018