Sagittaria is an aquatic weed in New South Wales, capable of aggressive growth and rapid spread.
This plant is a Weed of National Significance
This plant is a water weed
This plant must not be sold anywhere in NSW
Sagittaria spreads quickly and forms dense infestations in wetlands and natural watercourses where it can:
In irrigation channels and crops it:
Sagittaria is a perennial water weed up to 1.2 m tall.
It has three growth forms:
The leaves vary in shape and size and may be submerged or above the water.
Emergent (above water) leaves are:
Submerged (under water) leaves are:
Sagittaria has rhizomes and corms. The corms are:
Sagittaria looks similar to two other weeds:
Two Australian native plants also look similar:
Sagittaria grows in southern NSW, particularly in the Murray Irrigation District. It is common in the Greater Sydney and Hunter and also grows on the North Coast region. Isolated infestations are also present:
Sagittaria is native to North America. It was introduced as an ornamental plant. The first plant was identified in Australia in 1959 near Brisbane.
Sagittaria grows in warm temperate and subtropical climates. It grows best in sites with fluctuating water levels and silty sediment, including small channels and on the inside bends of rivers.
The broadleaf emergent form grows in warm, shallow and slow-flowing water. The submerged rosette form can grow in deeper water than the emergent forms. The different forms can grow together and submerged rosettes may grow amongst crowded broadleaf plants.
Frosts may kill or damage the above-water parts of the plants but the plants can regrow from the submerged parts.
Sagittaria grows in:
The broadleaf form of the plant can produce hundreds of thousands of seeds. Seed can float for up to 3 weeks before sinking and then remain dormant until conditions are right. Seed usually germinate from late winter to spring when there is an ideal amount of light and the outer seed coat has absorbed enough water. As well as flowing water, seeds are spread by animals including livestock and birds.
Sagittaria can reproduce from stems, root fragments, underground rhizomes and corms. These plant parts can be spread by floods or people dumping aquarium or pond plants. Corms are dormant through winter and produce new growth in spring, though they can remain viable in the soil for many years. Corms allow rapid regeneration of sagittaria following periods of stress.
Aquatic Plant Services (2004), The Biology and Control of Arrowhead, Goulburn-Murray Water.
Chapman, M. & Dore, D. (2006). Arrowhead Strategic Plan Final Draft, Gommalibee, Victoria: Rural Plan Pty Ltd.
Crocker, W. (1907), “Germination of seeds of water plants”, Botanical Gazette, Vol. 44, No. 5, pp. 375-380.
Department of Primary Industries Victoria, (2009), Invasiveness assessment - Giant Arrowhead (Sagittaria montevidensis) in Victoria, August 2010 http://www.land.vic.gov.au
Eastern & Western Riverina Noxious Weeds Advisory Group. (2004). Regional Weed Management Plan: Riverina Sagittaria Management Plan
Flower, G. (2003). The Biology and Control of Arrowhead (Sagittaria graminea). River & Catchment Health: Presenting current research in the Goulburn Broken Catchment.
Goulburn-Murray Water. (2001). Arrowhead Sagittaria graminea factsheet , Aquatic Plant Services.
Gunasekera, L. & Krake, K. (2001). Arrowhead – a serious aquatic weed in northern Victoria. In Victorian Landcare and Catchment Management, 19, 7.
Rataj, K. (1972). “Revision of the genus Sagittaria. Part I. (Old World Species)”, Annotationes Zoologicae et Botanicae, 76, pp. 1-36.
Turner, C.E. (2001). “Reproductive Biology of Sagittaria monetividensis Cham. & Schlecht. spp. Calycina (Engelm.) Bogin (Alismataceae)”, Unpublished doctoral dissertation, University of California, Berkeley.
Successful weed control relies on follow up after the initial efforts. This means looking for and killing regrowth or new seedlings. Using a combination of control methods is usually more successful.
Do not grow sagittaria in ponds and never dump aquatic plants in waterways.
If excavators or other machinery are used on sites with sagittaria they should be inspected and washed down before leaving the site.
Controlling water levels can limit the spread of sagittaria. Irrigation channels that constantly have water levels more than 1 m deep can prevent sagittaria from producing flowers and seeds.
To help prevent the spread of sagittaria when fishing or using waterways for other recreational activities:
Physical removal is useful near sensitive crops or for irrigation channels that cannot be closed during herbicide applications. Hygiene and containment measures are important during manual removal so that plant fragments do not float downstream and establish. It is also important when excavating to ensure the root and rhizome fragments in the soil are removed to avoid future regeneration. All machinery should be cleaned thoroughly before leaving the site.
Digging out sagittaria by hand can be used for small infestations and on sensitive sites where herbicide use is not appropriate. Remove all plant fragments, including rhizomes and corms in the soil and sediment.
Mechanical control can be effective:
Excavation can be labour intensive and expensive and care should be used so it does not damage the drain or channel structure.
Contact your local council for advice on how to dispose of sagittaria in your area.
A tablet form of herbicide is available for controlling sagittaria. The tablets may be put directly into the water or dissolved in water and then injected into the waterways. The volume of the water body needs to be calculated before using these tablets.
Additional accreditation is required to use table herbicides in waterways.
Trials using the fruit-feeding weevil Listronotus appendiculatus to control sagittaria are underway.
See Using herbicides for more information.
PERMIT 89861 Expires 30/11/2027
Glyphosate 360 g/L
(Only products registered for aquatic use)
Rate: 10 L product/100 L water
Comments: Spot spray. Only for use in Aquatic areas (Irrigation and drainage channels) within the Murrumbidgee Irrigation Limited areas of
responsibility. DO NOT exceed a maximum of 40 L product/ha. See permit for other critical comments.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate
Flumioxazin 15 grams /tablet
(Clipper herbicide®)
Rate: 1 tablet for every 37.5 cubic metres of water to achieve 400 parts per billion.
Comments: For use on dense or established weed populations in enclosed water bodies, deeper than 0.5 m and larger than 37.5 cubic metres, or margins of larger, still water bodies. Throw tablets directly into the water to achieve uniform distribution of the herbicide. At least 50% of the weed biomass must be below the water surface. See label for further instructions and restrictions.
Withholding period: 14 days before using treated water to irrigate food crops. See label for withholding periods for other uses of treated water.
Herbicide group: 14 (previously group G), Inhibition of protoporphyrinogen oxidase (PPO inhibitors)
Resistance risk: Moderate
Flumioxazin 15 grams /tablet
(Clipper herbicide®)
Rate: Inject solution into water body. 1 tablet per 37.5 cubic metres. Each tablet dissolved in at least 20L of water + 0.5 - 1.0% adjuvant/surfactant
Comments: For use on dense or established weeds in water bodies less than 0.5 m deep or with a volume less than 37.5 cubic metres. Dissolve tablets in water (at least 20L per tablet) mix thoroughly and then inject the solution directly into the water body.
Withholding period: 14 days before using treated water to irrigate food crops. See label for withholding periods for other uses of treated water.
Herbicide group: 14 (previously group G), Inhibition of protoporphyrinogen oxidase (PPO 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 |
Prohibition on certain dealings
Must not be imported into the state, sold, bartered, exchanged or offered for sale. |
Central Tablelands |
Regional Recommended Measure* (for Regional Priority - Eradication)
Land managers should mitigate the risk of the plant being introduced to their land. 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. Notify local control authority if found. |
Central West |
Regional Recommended Measure* (for Regional Priority - Prevention)
Land managers should mitigate the risk of the plant being introduced to their land. 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. Notify local control authority if found. |
Hunter |
Regional Recommended Measure* (for Regional Priority - Asset Protection)
Land managers should mitigate the risk of the plant being introduced to their land. 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. |
Murray
Core infestation zone: Berrigan Shire Council, Edward River Council, Murrumbidgee Council. Exclusion zone: Albury City Council, Federation Council, Greater Hume Council, Murray River Council, Snowy Valleys Council. |
Regional Recommended Measure* (for Regional Priority - Containment)
Within exclusion zone: Land managers should mitigate the risk of the plant being introduced to their land. 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. Notify local control authority if found. Within core infestation area: Land managers should mitigate the risk of the plant being introduced to their land. 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. |
North West |
Regional Recommended Measure* (for Regional Priority - Eradication)
Land managers should mitigate the risk of the plant being introduced to their land. 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. Notify local control authority if found. |
Riverina
Eradication whole of region except for Griffith. |
Regional Recommended Measure* (for Regional Priority - Eradication)
Land managers should mitigate the risk of the plant being introduced to their land. 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. Notify local control authority if found. Your local biosecurity weeds officer can help to identify, advise on control, and how to remove this weed. |
Western |
Regional Recommended Measure* (for Regional Priority - Prevention)
Land managers should mitigate the risk of the plant being introduced to their land. 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. Notify local control authority if found. |
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here |
Reviewed 2023