Artichoke thistle

Artichoke thistle is a perennial herb with blue to purple flowers.

Common name:

  • Artichoke thistle

Scientific name:

  • Cynara cardunculus L.

Other common names:

  • Wild Artichoke, Cardoon

Plant status

Catchment management authority boundaries

Catchment management authority boundaries
Regionally prohibited in the Goulburn Broken, North East and West Gippsland catchments

Regionally controlled in the Mallee, North Central, Corangamite, Port Phillip and Westernport catchments

Restricted in the Wimmera, Glenelg Hopkins and East Gippsland catchments

Plant biology

Artichoke thistle with purple flowers

Appearance

Herbaceous plant — Forb (flowering herbaceous plant — not a grass).

Description

Artichoke thistle is a perennial herb.

Stems

Stems are greyish-green. Mature plant stems are strongly ribbed, covered in cottony down on the underneath and branched near the top.

Generally, only 1 stem develops from each crown but up to 8 may be produced.

Leaves

Leaves are greyish-green on the upper surface and covered with a dense mat of white hair underneath.

Green leaves of artichoke thistle

Artichoke thistle forms a basal rosette of leaves which can grow out (horizontally) to 1m in length and 30cm wide and sends up a stalk in the centre (or stem leaf) which is smaller, about 15cm long.

All leaves are deeply divided containing a sharp yellow-orange spine along the margins.

Flowers

Florets are blue to purple with globular-shaped heads of 7 to 13cm diameter. These are surrounded by a series of stout bracts, each ending in a spiny tip.

Fruit

No fruit.

Seeds

Bears no fruit but seeds range from brown to black, 6 to 8mm long and are streaked lengthwise. They are equipped with a pappus of feathery hairs up to 4cm long that acts as a parachute to aid dispersal.

Fully grown Artichoke thistle

Growth and lifecycle

Method of reproduction and dispersal

Seeds from the plant are generally dispersed by wind, with most seeds only dropping a few metres from the parent plant. However, some seeds can travel up to 20 metres from the plant.

Seeds can also be spread by livestock, birds and flood.

Careless disposal of cut flowers and fragments of roots can also lead to the germination of new plants in favourable conditions. Soil movement may assist the spread of this plant.

Rate of growth and spread

The seedlings of the Artichoke thistle germinate year round but predominantly after the autumn rains.

Growth slows during winter becoming rapid during spring.

Plants may flower in the first year of growth but is generally delayed until the second summer.

Seedbank propagule persistence

Most Artichoke thistle seeds can survive up to five years in the soil.

Origin

Native of the Mediterranean.

Preferred habitat

Artichoke thistle prefers poorer pastures and neglected areas such as roadsides, creek and river frontages, industrial areas and waste lands. It grows mainly in medium to heavy soils and in areas where rainfall is between 500 to 700mm annually.

Distribution

There are many heavy infestations of this weed in Victoria.

Growth calendar

The icons on the following table represent the times of year for flowering, seeding, germination, the dormancy period of Artichoke thistle and also the optimum time for treatment.

 JanFebMarAprMayJunJulAugSepOctNovDec
FloweringFlowering stage" src="http://www.dpi.vic.gov.au/__data/assets/image/0003/103962/flowering.png Flowering stage" src="http://www.dpi.vic.gov.au/__data/assets/image/0003/103962/flowering.png Flowering stage" src="http://www.dpi.vic.gov.au/__data/assets/image/0003/103962/flowering.pngFlowering stage          Flowering stage
SeedingSeedling Stage" src="http://www.dpi.vic.gov.au/__data/assets/image/0006/103965/seeding.png Seedling Stage" src="http://www.dpi.vic.gov.au/__data/assets/image/0006/103965/seeding.png Seedling Stage" src="http://www.dpi.vic.gov.au/__data/assets/image/0006/103965/seeding.png Seedling Stage Seedling Stage          
Germination  Germination Stage Germination Stage Germination Stage        

Dormancy

            
Treatment        Treatment Stage Treatment Stage Treatment Stage 

Impact

Impact on ecosystems and waterways

Artichoke thistle displaces and impacts on native grasslands.

Some small birds feed on the seeds of the artichoke thistle and are responsible for increasing the spread along plantations, watercourses and fence lines.

Agricultural and economic impacts

Artichoke thistle has its greatest impact on agricultural land.

Once established, the weed shades out most pasture species as well as drawing moisture and nutrients from the soil.

The spiny nature of the plant deters sheep and cattle from grazing near heavy infestations. However, the plant will be eaten by livestock if no other food is available.

Social value and health impacts

The plant is reported to cause contact dermatitis in some people.

Management

Prescribed measures for the control of noxious weeds:

  • application of a registered herbicide
  • physical removal.

Read about prescribed measures for the control of noxious weeds.

Other management techniques

Changes in land use practices and spread prevention may also support Artichoke thistle management after implementing the prescribed measures above.

Page last updated: 12 Jul 2020