Silybum marianum
Environmental Weed (2024)
Common names
variegated thistle
Biostatus
Exotic
Category
Vascular
Structural class
Herbs - Dicotyledonous composites
Flower colours
Violet/Purple
Similar taxa
Erect biennial thistle growing up to 2.5m high and 2m wide; prominent white veins and blotches on spiny leaves which grow up to 60cm; large purple flowers are surrounded by spines and produce 50-200 black or brown seeds; seeds are 6-8mm long with downy hairs at one end.
Conservation status
Not applicable
Detailed taxonomy
Family
Asteraceae
Ecology
Flowering
November, December, January (February)
Fruiting
December-March
Year naturalised
1969
Origin
Mediterranean, S.W. Europe
Life cycle
Biennial or annual (dying off after setting seed in summer). Most wind dispersal is probably within 10m of the plant. Seed can be spread in hay, by water, in mud, agricultural produce and grain, on machinery or animals.
Other information
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
NVS code
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.
SILMAR