Maltese cockspur/Malta Thistle flowers and buds

Maltese cockspur

Centaurea melitensis​

Quick facts

Status
Permitted s11
Life Cycle
Annual or biennial
Growth Form
Herb
Origin
Southern Europe and northern Africa
Flowers
Yellow
Dispersal
Wind, water and animals

Names

Other Common Names: Cockspur Thistle, Malta Thistle

Synonyms: ​​Centaurea apula Lam​. 

Form and function

Flowers

  • Yellow florets arranged in flower heads (capitula).
  • Flower heads solitary or in groups of 2 to 3 and may be sessile or on short stalks.
  • Flower heads ovoid to globose and about 7 to 15 mm in diameter.
  • Base of flower head egg-shaped and covered with fine cobweb-like hairs.

Maltese cockspur flower and bud @ andysteed

Leaves

  • Alternately arranged along the stems.
  • Leaves sessile with bases often extending down the stem.
  • Leaves linear to narrowly lanceolate on upper stems.
  • Lower leaves are usually elongated and may be deeply lobed or shaped like a feather.
  • Leaf margins entire to toothed or lobed.
  • Terminal lobe usually largest and rounded.
  • Leaves are greyish green on both surfaces.
  • Leaf surfaces sparsely to densely rough (scabrid) with stiff hairs.
  • Leaves with small resin glands present.
  • Older leaves sometimes with fine white cottony hairs.

Maltese cockspur wilting and browning leaves © Andrea Kreuzhage

Seeds

  • Cypselae (seeds) that are dull white to grey or tan and sometimes with darker stripes.
  • 2 to 3 mm long.
  • Seeds covered with fine hairs (pubescent).
  • Pappus present with many unequal stiff bristles 1 to 3 mm long.

Maltese cockspur seed @ Government of Canada

Roots

  • Tap-rooted with a relatively shallow root system 

Habitat

This species can germinate in warm, dry and drought conditions and tolerates moderate salinity and soil pH levels. It is commonly found along roadsides, cultivated areas, rangelands, grasslands, open woodlands, and disturbed natural habitats.

May be confused with...

Similar non-native species: ​Similar to St. Benedict's thistle (Centaurea benedicta) however can be distinguished from C. melitensis in the shape of its flower heads.

How does it spread?

Dropped seeds are dispersed over short distances by wind, while long-distance spread occurs through the movement of people, animals, water, and contaminated soil.

Why is it a weed?

  • Displaces native plant species and impacts ecosystem structure.
  • Can reduce the ability of other plant species to reproduce.
  • Invades disturbed habitats but can also establish in undisturbed areas.
  • Competes strongly for resources including nutrients, light and water.

How to control

Arum Lily

Physical

Arum Lily

Chemical

Physical

​​Early detection and removal are essential for preventing establishment. Hand pulling and hoeing can be effective to control small infestation. While hand-pulling, make sure to remove as much of the taproot as possible. It is best to remove the plants when plants are either rosettes or before flowering to prevent the further spread of viable seeds. Hoeing also can be effective, if conducted repeatedly. Please discard the pulled plant in accordant with state/local requirement as unopened flowerhead may be self-fertilising and can produce viable seed. ​ 

Chemical

Chemical treatment is effective in post emergence from bolting to beginning of flowering, since lower rate of herbicide can be used.  

Seedling stage

​During the seedling stage, apply a mix of 15mL MCPA (570 g/L) in 10L of water using a foliar application method (e.g. backpack or knapsack sprayer) and spot spray seedlings until wet. Do not spray plants near waterways.

Rosette stage

During the rosette stage, apply a mix of 14mL 2, 4-D (625 g/L) in 10L of water using a foliar application method (e.g. backpack or knapsack sprayer) and spot spray seedlings until wet. Do not spray plants near waterways.

Actively growing

While plants are actively growing (plants over 15 cm high), spot spray using a foliar application method (e.g. backpack or knapsack sprayer) with glyphosate (360 g/L) at a rate of 75-100 ml in 15L of water or glyphosate (540 g/L) with a rate of 50-70 ml in 15L of water. If spraying near water, use a bioactive formulation.

Further
reading

Minor use permits
external link Permit PER96570 for MCPA and 2,4-D
external link Permit PER96570 for glyphosate

Weed Distribution Map

LSID number: [51268021] | full LSID: [https://id.biodiversity.org.au/taxon/apni/51268021] | field_lsid: [] | taxon: [Centaurea melitensis​]

ALA Reference

References

  • Atlas of Living Australia. (n.d.) Centaurea melitensis L
  • Department of Natural Resources and Environment Tasmania. (n.d.). Herbicides for Variegated Thistle Control.
  • FloraSA. (n.d.) Centaurea melitensis. Flora of South Australia.
  • Humphries, T., Weller, S.L., Mahony, A., Javaid, M.M., Turville, C. & Florentine, S. (2024) Seed ecology of the arid zone invasive thistle; Centaurea melitensis L.: A study of the effects of seasonal temperature, pH, salinity and moisture stress. Weed Research, 64(6), 445–455.
  • Lurdes sarmiento. (n.d.). Centaurea melitensis: Characteristics, Ecology and Impact as an Invasive Plant.

Life Cycle

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Notes
Germination
Active growth
Flowering
Fruiting
Regularly or most commonly
Occasionally, given suitable conditions

Management

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Notes
Hand removal
Chemical Treatment
Optimal
Potentially, but conditionally dependent
Last updated: October 2026