NSW WeedWise

Orange hawkweed (Pilosella aurantiaca)

PROHIBITED MATTER: If you see this plant report it. Call the NSW DPI Biosecurity Helpline 1800 680 244
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Orange hawkweed is a small herb that has orange daisy flowers. It invades native vegetation in alpine regions and can invade pastures, reducing productivity.

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Control

Biosecurity duty

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How does this weed affect you?

Orange hawkweed forms dense stands with thousands of plants per square metre. It is a significant threat to biodiversity in the alpine regions in Australia. Orange hawkweed:

  • outcompetes native plants especially native grasses in alpine regions
  • reduces food and habitat for native animals
  • competes with pastures and reducing productivity
  • invades gardens and roadsides.

What does it look like?

Orange hawkweed is a perennial herb with rosette leaves and clusters of orange flowers on stems up to 40 cm tall. The plant produces multiple daughter plants from stolons and rhizomes.

Leaves are:

  • oblong, oval or spoon-shaped and without stalks
  • usually 6-20 cm long and 1-6 cm wide (but up to 30 cm long and 7 cm wide) 
  • usually very hairy on both sides with long white hairs
  • smooth or slightly toothed on the edges
  • sometimes ‘sticky’ to touch
  • at the base of the plant in a rosette and occasionally at the bottom of the flower stem

The leaves release milky sap when broken.

Flowers are:

  • orange to orange-red with yellow centres (turning purple when dry)
  • daisy-like with square-ended petals
  • 1–2 cm in diameter 
  • surrounded at the base by green hairy bracts
  • in clusters of 5–25 flowers on the end of the flowering stalks
  • present from spring to summer. 

Seeds are:

  • purplish-black
  • ribbed with a tuft of bristles on one end, up to 6 mm long

Stems:

  • are up to 40 cm long
  • are covered in short stiff hairs
  • release a milky sap when broken.

Roots are

  •  shallow and fibrous.

Similar looking plants

Orange hawkweed looks similar to:

  • Other species of hawkweeds, but these all have yellow flowers.
  • Dandelions (Taraxacum officinale), which have leaves that are often deeply divided/lobed and one yellow flower per stem. They do not have stolons or rhizomes.
  • Flatweeds (Hypochaeris species), which have yellow flowers on branched hairless stems. They do not have stolons or rhizomes.

Where is it found?

Orange hawkweed is native to northern and central Europe. 

In NSW, orange hawkweed was previously sold by nurseries on the south coast and southern highlands. The first naturalised plants were found in 2003 in Kosciusko National Park. 

What type of environment does it grow in? 

Orange hawkweed grows in cool temperate and alpine environments. It is frost tolerant and can grow on a wide range of soil types. It prefers an annual rainfall above 500 mm and the seedlings are sensitive to dry conditions. 

Most plants have been found in alpine or subalpine climates. It grows in grasslands, eucalyptus woodlands with grassy understorey, alpine heathlands and in pastures. Plants are often found in areas where the soil has been disturbed. 

Maps and records

  • Recorded presence of Orange hawkweed during property inspections (Map: Biosecurity Information System - Weeds, 2017-2024)
    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 seed 

Hawkweed plants can mature in approximately 5 months. Infestations can produce up to 40,000 seeds per square metre. Some seeds may remain viable in the soil for up to 5 years. Mass germination occurs after rain. The seeds have tufts that help the seed attach to hair, fur, and vehicles. Seeds can be spread by: 

  • wind and water 
  • sticking to boots, clothing and camping or other recreational equipment 
  • attaching to animals 
  • sticking to vehicles, ski machinery or slashers 
  • movement of contaminated seed. 

By plant parts 

Plants form dense mats via rhizomes and stolons that spread out from a parent plant. Each hawkweed plant produces up to eight stolons which produce daughter plants. New plants can grow from root fragments and root buds. 

References

Cousens, R. D., & Williams, N. (2011). Improved detection and eradication of hawkweed (Hieracium). Rural Industries Research and Development Corporation.

CRC (2003). Orange Hawkweed Weed Management Guide (2003) CRC for Weed Management.

Hamilton, M.A. Cherry, H. Turner, P.J. (2015)\. Hawkweed eradication from NSW: Could this be ‘the first’?. Plant Protection Quarterly Vol.30(3): 110-115

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved November 2022 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Pilosella~aurantiaca

Williams, N. S. G., Hahs, A. K., & Morgan, J. W. (2008). A dispersal-constrained habitat suitability model for predicting invasion of alpine vegetation. Ecological applications, 18(2), 347-359.

Williams, N.S.G. and Holland, K.D. (2007). The ecology and invasion history of hawkweeds (Hieracium species) in Australia, Plant Protection Quarterly, 22(2): 76-80

More information

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Control

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.

Herbicide options

WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.

PERMIT 14558 Expires 30/06/2024
Clopyralid 300 g/L (Lontrel®)
Rate: 5 mL in 1 L of water
Comments: Spot spray application only for National Parks and non-agricultural adjoining lands. Only for use by NPWS employees and contractors, See permit for further critical comments.
Withholding period: 1-12 weeks (see label).
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

PERMIT 14928 Expires 30/09/2024
Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L (Grazon Extra®)
Rate: 250-500 mL per 100 L plus BS 1000 or equivalent at 100 mL per 100 L
Comments: Spray actively growing plants before flowering. Do not apply more than once per season. See permit for critical comments.
Withholding period: Where product is used to control woody weeds in pastures there is a restriction of 12 weeks for use of treated pastures for making hay and silage; using hay or other plant material for compost, mulch or mushroom substrate; or using animal waste from animals grazing on treated pastures for compost, mulching, or spreading on pasture/crops.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

PERMIT 14928 Expires 30/09/2024
Triclopyr 300 g/L + Picloram 100 g/L (Various products)
Rate: 250-500 mL per 100 L plus BS 1000 or equivalent at 100 mL per 100 L
Comments: Spray actively growing plants before flowering. Do not apply more than once per season. See permit for critical comments.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

PERMIT 14301 Expires 31/07/2026
Picloram 20 g/kg (Tordon® Granules)
Rate: 45 g/m2
Comments: Granular application only in Kosciuszko National Park and lands in the Snowy Monaro Regional Council area. See permit for further critical comments.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
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 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 in the genus Pilosella are Prohibited Matter

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For technical advice and assistance with identification please contact your local council weeds officer.

Reviewed 2024

www.dpi.nsw.gov.au