Vascular – Exotic
Herbs - Dicotyledonous composites
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
Terrestrial. A plant of roadsides, pasture, wasteland and amongst crops such as lucerne. Will grow in most soil types.
An erect thistle growing to 1.6m high (commonly 80-120cm), with a stout, branched, fleshy taproot up to 40cm deep. Rosette leaves are usually long, narrow and deeply cut into many narrow lobes with spiny edges and green and only sparsely hairy on both surfaces. The upper surface of the leaf often has a metallic sheen and a whitish marginal zone, especially at the base of the spines. Flowering stems are erect (up to 1.5m) and a purple flower head which droops. Seeds are large, heavy (3-4mm long) with a pappus of fine toothed bristles 15-25mm long.
Can be distinguished by the large distinctive nodding flower heads.
November, December, January, February
Eurasia, N Africa
carduus: From the Greek word kardos which means thistle.
Reason For Introduction
Life Cycle Comments
Annual or Biennial. Seed germinates in the late summer, early autumn but has the ability to germinate at any time of the year. Seed germinates late summer to early winter, but germination also occurs in spring or summer if adequate moisture is available. Seed that germinates in autumn, remains vegetative during the first summer and flowers in the second summer, hence biennial.
The plant is dispersed by seed only.
Seed may lay dormant in the soil for up to twenty years. Approximately 200 seeds produced per flower head of which two-thirds are viable.
Seed is dispersed locally by wind and also spread in mud, water, machinery, fodder and agricultural seed. 91% of seed falls within 1-2 metres of the plant and only a few were detected more than 10 metres away (Department of Conservation 1996).
Physical damage that may prevent flowering results in the persistance of the plant until flowering occurs.