Artichoke thistle (Cynara cardunculus)

Also known as: wild artichoke

Artichoke thistle has long prickly leaves and large blue-purple or sometimes pink flowers. It competes with pastures, crops and native plants.

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How does this weed affect you?

Thistles are invasive weeds of pasture, reducing carrying capacity. Artichoke thistle has the ability to dominate the vegetation of an area once it becomes established. The large plants smother most pasture growth as well as drawing much moisture and nutrient from the soil. It may also compete with crops and impede harvesting operations. The prickly nature of the leaves deters sheep and cattle from areas of heavy infestation.

What does it look like?

Artichoke thistle is a perennial herb that grows up to 2 m tall. Seedlings grow slowly through winter. Plants have a rosette of grey-green leaves at the base which may die off over summer. New leaves grow in autumn and plants usually start to flower in their second summer.

 Leaves are:

• greyish-green and sparsely hairy on the upper surface
• whitish with dense, slightly sticky, cobweb-like hairs below
• usually up to 50 cm long and 35 cm wide but the rosette leaves at the base can be up to 90 cm long.
• deeply divided with many lobes with yellow-orange spines along the edges
• in a rosette at the base
• alternate along the upright stems.

Flowerheads are:

• dense, very spiny thistle heads, 5-13 cm in diameter
• flower bristles are blue-purple; sometimes whitish or pink; up to 5 cm long
• single, on thick stalks at the end of branches.

Stems are:

• ribbed and sparsely covered in cobweb-like hairs
• branched at the top.

 There is usually one stem growing from a rosette. Occasionally rosettes have up to 8 stems.

Where is it found?

In NSW, artichoke thistle is quite rare; it has mostly been found in the Riverina, Murray, Western and Central West Regions.

Artichoke thistle is a native of the Mediterranean regions. 

How does it spread?

By seed

Each plant can produce up to 30,000 seeds per year. The seeds can be spread by the wind for up to 40 m, though most seeds fall within 6 m of the parent plant. Seeds are also spread by:

• moving water
• contaminated mud or soil
• sticking to animals including sheep cattle and birds
• dumping floral arrangements.

By plant parts

Plants also grow from root or crown fragments which can be spread by cultivation equipment.

What type of environment does it grow in?

 Artichoke thistle grows mainly on medium to heavy soils.

References

Bean, A. R. (2015). Cynara cardunculus subsp. flavescens, Asteraceae Subfam. 2. Carduoideae Trib. 1. Cardueae. In A. J. G. E. Wilson (Ed.), Flora of Australia (Vol. 37, pp. 61– 62). Melbourne: CSIRO publishing.

Biosecurity Queensland (2016). Weeds of Australia: Cynara cardunculus. Retrieved 28 August 2020 from: https://keyserver.lucidcentral.org/weeds/data/media/Html/cynara_cardunculus.htm

Marushia, R. G., & Holt, J. S. (2006). The effects of habitat on dispersal patterns of an invasive thistle, Cynara cardunculus. Biological Invasions, 8(4), 577-594.

Marushia, R. G., & Holt, J. S. (2008). Reproductive strategy of an invasive thistle: effects of adults on seedling survival. Biological Invasions, 10(6), 913-924.

Parsons, W. T., Parsons, W. T., & Cuthbertson, E. G. (2001). Noxious weeds of Australia. CSIRO publishing.

Richardson, F. J., Richardson, R. G., & Shepherd, R. C. H. (2011). Weeds of the south-east: an identification guide for Australia (No. Ed. 2). CSIRO.

Uddin, M. N., Asaeda, T., Shampa, S. H., & Robinson, R. W. (2020). Allelopathy and its coevolutionary implications between native and non-native neighbors of invasive Cynara cardunculus L. Ecology and evolution, 10(14), 7463-7475.

White, V. A., & Holt, J. S. (2005). Competition of artichoke thistle (Cynara cardunculus) with native and exotic grassland species. Weed Science, 53(6), 826-833.

More information

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Control

Herbicide options

See Using herbicides for more information.

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Dicamba 750 g/L (Kamba® 750)
Rate: 1.1 L/ha Use a minimum of 1500 L solution per ha. Add a surfactant.
Comments: Boom spray for non-crop situations. Spray prior to flowering.
Withholding period: Do not harvest, graze or cut for stock food for 7 days after application.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Dicamba 750 g/L (Kamba® 750)
Rate: 67 mL per 100 L of water. Add a surfactant.
Comments: Spray prior to flowering. For non crop situations.
Withholding period: Do not harvest, graze or cut for stock food for 7 days after application.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Dicamba 750 g/L (Kamba® 750)
Rate: 16 mL per 15 L of water. Add a surfactant.
Comments: Spot spray prior to flowering. For non-crop situations.
Withholding period: Do not harvest, graze or cut for stock food for 7 days after application.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Glyphosate 360 g/L (Various products)
Rate: 10 ml per 1 L water
Comments: Spot spray. For general weed control in domestic areas (home gardens), commercial, industrial and public service areas, agricultural buildings and other farm situations.
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.

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Reviewed 2021