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Orange hawkweed (Pilosella aurantiaca)

Orange hawkweed is an invasive environmental weed that can establish in intact native vegetation as well as disturbed sites. It is currently recorded in relatively few, localised areas of Australia, but can spread rapidly and may displace native plants and pasture species.

Key facts

Type: Weed, herb.

Native to: North and Central Europe, extending to southern France and Bulgaria.

Established in: NSW, VIC, TAS.

Other names: King Devil Hawkweed, Devil's Paintbrush, Fox and Cubs, Grim the Collier.

Best time to act: Plants flower in summer, mainly December and January, most fruiting is finished during February, with some as late as March, and seedlings commonly establish in autumn.

Identification

  • A hairy herb with leaves growing in basal rosettes; broken stems and leaves exude milky sap.
  • Leaves are about 150 mm long and 30 mm wide, with fine, spreading hairs on both surfaces.
  • Lateral leafy runners take root and form new leaf tufts.
  • Flower heads are bright reddish-orange, about 15 to 30 mm across, and clustered at the top of an erect, leafless stem about 350 mm long.
  • Narrow seeds are about 2 mm long and have a pappus of silky hairs about 6 mm long.
  • Look-alike: King Devil Hawkweed (Hieracium praealtum subsp. bauhinii) usually has taller flowering stems, up to 70 cm, and bright yellow rather than orange flower heads.
  • Look-alike: Other daisy-family plants may resemble hawkweeds when not flowering, but few have the copious fine, spreading hairs characteristic of the hawkweeds established in Australia.

Where it grows

In Australia it occurs in cool, high-rainfall areas, including alpine and subalpine vegetation, woodlands, grasslands and heathlands, as well as disturbed sites, gardens and lawns.

Why it matters

  • It can invade intact native vegetation and rapidly form dense mats of rosettes.
  • It may reduce botanical biodiversity by competing with native herbs in alpine and subalpine grasslands and woodlands, including some rare or threatened species.
  • It can become a significant weed in lawns and gardens.
  • It may indirectly affect livestock by displacing potentially more nutritious pasture species.

How it spreads

  • Runners spread the plant locally, while wind-blown seeds can disperse over longer distances; a one-square-metre mat can produce up to 40,000 seeds a year.
  • Seed may also spread in water or in soil caught on vehicles and soil-moving equipment; inadvertent transport on hikers' boots or equipment is also a possible pathway.
  • Plant fragments in moved soil can spread the weed, and established plants regrow from short below-ground rhizomes.

Control options

  • Report new outbreaks immediately to the relevant state or territory weed management agency or local council.
  • Do not attempt control without expert assistance, as poorly performed or incomplete control can spread the weed and worsen the problem.
  • Careful application of registered herbicides has been used successfully; follow expert advice and applicable product directions.
  • Small plants may be dug out only after careful assessment, because fragments can spread the plant or roots left in the soil can resprout.

Hygiene and washdown

  • Check and clean vehicles, machinery and equipment to avoid moving seed in caught soil.
  • Avoid carrying seeds or plant fragments on boots or in moved soil, and take care with soil movement because water dispersal is also a likely pathway.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): National Environmental Alert List. One of 28 weeds named on the National Environmental Alert List as early-stage invaders with serious potential to harm the environment.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Prohibited matter. It is an offence to deal with it, and you must notify NSW DPIRD as soon as you become aware of it.
  • Victoria: State prohibited weed. State prohibited weeds are the highest priority: the Victorian Government is responsible for eradicating them, so report any sighting to Agriculture Victoria.
  • South Australia: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • Australian Capital Territory: Declared pest, notifiable, prohibited. It is a declared pest throughout the ACT. You must report it to ACT Biosecurity. Dealing with it, such as selling, moving or keeping it, is prohibited.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania

Sources