Quick Facts

Quick facts

  • Nodding Thistle (Carduus thoermeri) is a species in the "Carduus nutans group", a taxonomically complex group.
  • Nodding Thistle is currently only naturalised in a restricted part of south-eastern Queensland.

What Does It Look Like?

What is it?

Nodding Thistle (Carduus thoermeri) is a coarse erect annual herb to 1.5 m tall. Its erect stems are glabrous (hairless) with spiny wings about 3–8 mm wide. Leaves are green and also glabrous. The lower leaves are up to 40 cm long by 7.5 cm wide, while upper leaves are smaller. Each leaf is deeply lobed, with marginal spines 2–7 mm long.

Solitary terminal flower-heads form on the main stems and on the lateral branches, on stalks (peduncles) 10–40 mm long. The largest heads are 35–60 mm diameter. Heads droop or "nod" to one side when mature, leading to the common name. Each head consists of several rows of glabrous, green to purplish spine-tipped phyllaries (floral bracts or modified leaves) surrounding a large number of purple narrowly tubular flowers. Each flower is about 19–26 mm long.

The seeds or achenes (fruit) are smooth, yellow-brown with darker longitudinal bands, 3.5–4.1 mm long and ellipsoid in shape with a terminal pappus of unbranched white hairs to 17–23 mm long (Tutin et al. 1976; Stanley & Ross 1986)

Carduus thoermeri is a species in the "Carduus nutans group", a taxonomically complex group. In a manuscript recently prepared for Flora of Australia both Carduus thoermeri and C. nutans are recognized as distinct species (Bean, unpubl. manuscript).

For further information and assistance with identification of Nodding Thistle contact the herbarium in your state or territory.

Flower colour


Growth form (weed type/habit)


Where it currently grows? Preferred habitat

Nodding Thistle (Carduus thoermeri) inhabits fertile soils often on alluvial flats (Bean, unpubl. manuscript).

Are there similar species?

Carduus thoermeri differs from Carduus nutans in the lack of cobwebby hairs on stems, leaves, floral bracts (distinctly cobwebby-hairy in C. nutans) (Bean, unpubl. manuscript), and having florets widest in the middle and narrower at the base compared with C. nutans where the middle is no wider than the base (Tutin et al. 1976).

Other Thistles occurring in southern Australia with pinkish purple flowers and greenish leaves are the Slender Thistles (Carduus pycnocephalus and Carduus tenuiflorus) and Spear Thistle (Cirsium vulgare). Carduus thoermeri differs from all of these most obviously by its nodding flowerheads and hairless leaves, stems and floral bracts (Tutin et al. 1976)

Why Is It A Weed?

What are its impacts?

It is presumed that Carduus thoermeri would behave like the closely related Carduus nutans (also known as Nodding Thistle) and become a problem in pastures.

Agriculture: In pastoral areas Carduus nutans forms dense patches of spiny plants and may occupy considerable areas of pasture out-competing desirable pasture species and reducing carrying capacity. The spines deter stock and thistle exudates restrict growth of nearby pasture (Popay & Medd 1990; Parsons & Cuthbertson 1992).

Seed production for Carduus nutans is high and seed longevity is habitat dependent being up to about 7 years in bare or cultivated ground and up to about 13 years in pasture (Popay & Medd 1990; Parsons & Cuthbertson 1992).

Native ecosystems: In native grasslands Carduus nutans is invasive in disturbed areas along tracks and areas of animal disturbance and can persist if unchecked (Popay & Medd 1990; Parsons & Cuthbertson 1992).

How does it spread?

No information is currently available. It is presumed that Carduus thoermeri would behave like the closely related Carduus nutans (also known as Nodding Thistle).

Carduus nutans reproduces only by seed. The seed develops with a pappus (a tuft of silky hairs) on one end but this easily falls off and does not aid dispersal. Most seed falls from the head within 2 m of the base of the plant, rarely more 10 m from the plant. Longer distance dispersal has been through human activity, on machinery, in soil, on livestock, in hay and as a contaminant of agricultural seed (Popay & Medd 1990; Parsons & Cuthbertson 1992; Woodburn & Sheppard 1996).

What is its history in Australia?

Details of the introduction of Nodding Thistle to Australia are unknown.

How To Manage It?

Best practice management

It can be assumed that the same control management used on Carduus nutans (also known as Nodding Thistle) would work for Carduus thoermeri.

Biological control: Nodding Thistle  has been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. Biological control of Nodding Thistle in Virginia, Missouri and Montana in the United States has been achieved with a combination of three thistle herbivores (Rhinocyllus conicus, Trichosirocalus horridus and Cassida rubiginosa) and a rust fungus (Puccinia carduorum). Nodding Thistle biological control is achieved in about 5–6 years in Virginia. Development and reproduction of the three thistle herbivores are not adversely affected by the rust while the rust hastens plant senescence and reduces seed production (Kok 2001).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au .

Does it have a biological control agent?


When does it grow? (lifecycle/growth calendar)

No information is available.

Where Is It Found?

Which states and territories is it found?


What areas within states and territories is it found?

In Australia Nodding Thistle (Carduus thoermeri) occurs in south-eastern Queensland, restricted to the area between Dalby, Kingaroy and Gympie (Bean, unpubl. manuscript). Its current abundance is unknown (Cunningham et al. 2004).

Where does it originate?

Nodding Thistle (Carduus thoermeri) is native to western Asia, eastern and southern Europe including Russia (Tutin et al. 1976).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?


Where is it a declared weed?

Not declared in any Australian state or territory

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?


Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?


Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Carduus thoermeri

Other scientific names (synonyms)?


Does it have other known common name(s)?

Musk Thistle

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