Nodding Thistle

Carduus nutans L. ssp. nutans

Family: - Asteraceae.


Carduus is derived from the Greek kandos meaning thistle or the Greek cheuro, a technical term used in the carding of wool where the heads of some of the species were used.

Nutans is from the Latin word nuto meaning to nod referring to the nodding habit of the flower heads.

Nodding Thistle refers to the nodding habit of the flowering stems and its spiny or thistle like form.

Other Names:

Musk Thistle


Annual or biennial, erect and bushy in habit with stems that branch from the base and along their length. It can reach 1500 mm or more in height and frequently the same in diameter. The flower heads are large (40-80 mm diameter), nodding and pink to purple or rarely white. The bracts under the flower head are often strongly bent back.



Two. The cotyledon is 10 to 15 mm long and hairless with a short, broad, merging petiole. It normally has a distinct white vein up the centre. The seedling has neither hypocotyl nor epicotyl. Tip rounded. Sides convex. Base tapered.

First leaves:

The leaves grow singly but the first two emerge close together and often appear paired. The first leaf reaches 20 to 30 mm in length and has a petiole, which is about one quarter the length of the leaf. The margin has small spined lobes. The early leaves have a pale veining and carry short, scattered hairs on the upper surface and only a few or none on the lower surface.



Stipules -

Petiole - None.

Blade - Light grey green, 300-500 mm long, deeply or pinnately lobed into triangular lobes, often with whitish margins and armed with 3 mm long spines. The margin is wavy and the upper and lower surfaces carry long hairs which are numerous on the mid-rib but sparser or absent on the rest of the leaf. The midrib is often white.

Stem leaves - The stem leaves are 300 to 400 mm long, grey green or metallic green, deeply divided, with short rigid spines and sessile, with their margins continued down the stem as wings. There are no wings on the vein. They carry short mealy hairs on the upper surface, and similar but rather larger hairs on the lower surface especially on the veins.


The stem is polygonal in cross section, ridged, thick and solid with a small pithy core. It is many branched from the base and along their length. Up to 1600 mm long and usually 800-1200 mm. The stems carry long, downy, thin hairs that may form a cobwebby mat. The stem is almost invariably bent over to give the plant its characteristic 'nodding' habit. Winged (except just below the flower head) and spiny. Multiple stems are produced if the crown is damaged.

Flower head:

The inflorescences are composite type and usually single and terminal on leafless nodding branches. It is hemispherical, 40 to 80 mm in diameter with many tubular and ligulate florets, pink, red, purple or occasionally white in colour, strongly and sweetly scented and may be covered with cobwebby hairs. The flower head may be stalkless or on short stalks. The head is surrounded by many, spiny, often purplish bracts. The outer bracts are bent backwards and the inner bracts are papery. Flowers droop or nod at right angles to the stem at maturity.


Bracts - Many, spine tipped.

Ovary -

Stamens -

Anthers - Arrow shaped.



Grey to yellow brown, shiny, slightly curved, 3-4 mm long, longitudinal faintly dotted lines. There is a rim below the cone shaped tip at the pappus end of the seed. A tuft of fine toothed, 15-25 mm long bristles on top. The pappus is large compared to the seed and readily detaches.


Stout, fleshy, branched taproot to 400 mm deep.

Key Characters:


Life cycle:

Annual or biennial. Germination can occur at most times of the year if there is sufficient soil moisture. There is usually a flush of germination following rains in autumn. They then grow a large rosette of leaves over the winter to spring period, become dormant over their first summer, re commence growth in autumn and flower in the following summer and then die. Some plants may flower in their first season. Plants in all stages of growth can often be found at most times of the year.

Plants damaged by slashing, cultivation or trampling tend to become perennial.


Plants must experience low temperatures before they will form flowering stems.


By seed.

Flowering times:

Mainly late spring to autumn in NSW.

Mainly throughout winter in TAS.

Seed Biology and Germination:

Seed passes through stock without loosing viability.

Individual plants commonly produce 7000 seeds and up to 20,000 have been recorded.

Seed longevity depends on the depth of burial. Seed buried more than 50 mm deep may survive for 10 years, whilst surface seed loses viability after 2-4 years.

Far red light, present in shaded situations, inhibits germination of the seeds. Germination is usually greatest in open situations.

Vegetative Propagules:

Crowns may re shoot if damaged.



It produces toxins, which inhibit the growth of some companion species, thus increasing its competitiveness.

Population Dynamics and Dispersal:

Seed is dispersed mainly as contaminants of produce such as hay and grain, by tangling in wool, fur or clothing and in dung, mud and water. Dispersal by wind is probably variable because the pappus readily separates from the seed. In New Zealand studies, 91% of seed falls within 1-2 metres of the parent plant and none was found more than 10 metres from undisturbed plants. However, American studies have shown that seed can be carried over 100 metres in a 20 kph wind.

Seedling densities of 100-200 occur but these usually self thin to dense patches of around 10 plants/m2. Rosettes up to a metre in diameter crowd out companion species.

Autumn germinations have a greater chance of survival than later germinations.

It commonly invades annual pastures especially where legumes have been planted and fertilisers applied or where the soil has been bared. It rarely establishes in strong perennial pastures.

Origin and History:

Europe an Asia.

First recorded in NSW in 1950. By 1980 it had infested 50,000 square kilometres. It was found in WA in 1976 and in SA in 1978 and has been eradicated.

Probably imported into Australia in the 1940's as a contaminant of pea or pasture seed from New Zealand.

Imported into Tasmania as an impurity in ryegrass seed.



Nodding Thistle is found in many parts of Tasmania, but is very localised due to its importation into Tasmania as an impurity in ryegrass seed.


Open situations



More common in the regions with an annual rainfall of 500-900 mm.


Prefers moist, highly fertile, well drained sites but grows on a wide range of soil types.

Prefers dry alkaline soils in its native range.

Plant Associations:



Flower heads eaten by stock.

Dried flower heads have been used to curdle milk.

The pith of the stem is used as a boiled vegetable.

Nectar produces a quality honey.


Serious weed of pastures and crops.

Contaminates wool.

It is extremely competitive, continuing to grow vigorously and flower throughout the Winter.

Weed of stockyards, holding paddocks, roadsides, railway lines.

Harbours vermin.

Thick infestations are avoided by stock because of its spiny nature and this can seriously reduce the carrying capacity of pastures.


Not recorded as toxic.


Noxious weed of NSW, SA, TAS,VIC and WA.

Management and Control:

It is the subject of an eradication campaign in Tasmania and has been eradicated in SA and WA.


1 plant/m2 can cause loss of carrying capacity in pasture.

Eradication strategies:

Establish a perennial pasture to reduce or prevent seedlings establishing. Repeated cultivation to 100 mm deep will provide control. Remove isolated plants by hand. Herbicides such as Clopyralid, MCPA and 2,4-D are most effective on young actively growing plants and when the buds first appear. Applications in winter and at the stem elongation are less effective. Hexazinone and bentazone is used in lucerne pastures.

Mowing and slashing are generally ineffective. Viable seeds may mature in the heads of mown plants and plants often re shoot from buds at the base of the plant.

Herbicide resistance:

Populations resistant to MCPA and 2,4-D have developed after repeated use in New Zealand.

Biological Control:

Bio control with the Nodding thistle receptacle weevil and a crown weevil has been successful in Canada and USA. Bio control has had little effect in New Zealand. Two weevils and a seed fly have been released in Australia. Rusts are being investigated.

Related plants:

Nodding Thistle (C. thoermeri)

Plumeless Thistle (C. acanthoides)

Slender Thistle (C. pycnocephalus)

Winged Slender Thistle (C. tenuifolius)

Plants of similar appearance:

Young plants are most likely to be confused with Slender or Californian Thistles. Nodding Thistle leaves are relatively longer and narrower than those of Slender Thistle, and tend to have a greater number of lobes. The lobes in Nodding Thistle are often completely separated from each other. The surface of Californian Thistle is shinier, while the general shape of the leaf is less regular and symmetrical. In mature plants the Nodding Thistle flowers are distinctive, while its spreading and bushy growth habit is unlike that of either of the other two species.

C. thoermeri is very similar and also called Nodding Thistle. It occurs in Queensland and can be distinguished by its unbranched stems, leaves with a silvery sheen, flowers on long leafless stalks, flower bracts in the middle row are wider above a constricted zone than at the base and they taper abruptly to a short spine.

Plumeless Thistle (C. acanthoides) a serious weed of America has smaller purple flowers and flower bracts that are not constricted.


Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P88. Photo.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P723.

Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P28-29. Diagram.

Hyde-Wyatt, B.H. and Morris, D.I. (1980) The Noxious and Secondary Weeds of Tasmania. (Tasmanian Department of Agriculture, Hobart, Tasmania). P26-27. Diagram.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #252.1.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P186. Photos.


Collated by HerbiGuide. Phone 08 98444064 or for more information.