Perennial thistle control

Page last updated: Wednesday, 18 January 2017 - 11:47am

Please note: This content may be out of date and is currently under review.

Control methods for perennial thistle (Cirsium arvense) a declared pest in Western Australia.

Report the presence of this pest before undertaking control

Information about this pest can be found on the perennial thistle: declared pest page.

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Chemical requirements

When using any agricultural chemicals please ensure that you always follow instructions on the label and any permit. Users of agricultural chemical products must always strictly comply with the directions on the label and the conditions of any permit. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website.

Control options

Chemical control options can be found below. For other methods of control please refer to the declared plant control handbook.

Chemical control options

Recommended herbicides

Rosette to flowering:

Picloram + 2,4 D amine

Actively growing:


Herbicide: Picloram + 2,4 D amine (Group I)

Active ingredient

75g/L picloram + 300g/L of 2,4-D

Rates of dilution for spot spraying


Amount of product/10L water


Rate of product/ha

Not recommended

Time of application

Winter-spring rosette to flowering stage. Optimum stage is during budding.


Re-treatment may be necessary as surviving rootstocks will reshoot.

More information and other control methods

Grubbing and cultivation ineffective due to ability to reshoot from rootstock and root fragments. Treatment is residual and will control most broadleaved plants for one or two growing seasons. Triclopyr + picloram formulation would probably do the same control.

Herbicide: Clopyralid (Group I) (various trade names: see APVMA link)

Active ingredient

300mL/L and 750g/kg clopyralid

Rate of product use

  • 80 - 160mL for seedling/rosettes up to 15cm diameter/height
  • 320mL rosettes >15cm diameter/height up to flowering
  • 200 – 400g for seedling/rosettes <15cm diameter/height
  • 800g for seedling/rosettes >15cm diameter/height


Seedlings – just prior to flowering

Further information

Rates of liquid clopyralid appear to be too low so the 750g formulation preferred.

Herbicide: Glyphosate (Group M) (various trade names: see APVMA link)

Active ingredient

360, 450, 490, 500 and 540g/L and 680g/kg glyphosate

Rates of dilution for spot spraying

1:100 for 360g/L

Amount of product/10L water

  • 100mL for 360g/L concentration
  • 0mL for 450g/L concentration
  • 70mL for 490 and 500g/L concentration
  • 65mL for 540g/L concentration
  • 50g for 680g/kg concentration
  • 40g for 840g/kg concentration

Rate of product per hectare

Not recommended

Time of application

Actively growing at flowering


Avoid cultivation prior to treatment. Re-treatment may be necessary.

More information and other control methods

In wet areas use only approved glyphosates such as Roundup® Biactive and Razor®.

Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080