Ontario Wildflowers website

Canada Thistle
Cirsium arvense

Canada Thistle (Cirsium arvense) Other common names: Creeping Thistle

Other scientific names: Carduus arvensis, Cirsium lanatum, Cnicus arvensis, Serratula arvensis

Family: Composite Family (Asteraceae)

Group: Thistles

Flowers: Summer;  Blue/Violet;  Indistinguishable parts (petals)

Leaves: Alternate, Simple

Habitat: Fields and Open Areas

Books: Newcomb's Wildflower Guide: 430   

Native/Non-native: Non-native

Origin and Meaning of Names:
 Scientific Name: arvense: of cultivated ground


Photographs: 155 photographs available, of which 14 are featured on this page. SCROLL DOWN FOR PHOTOGRAPHS.

Range Map is at the bottom of the page

Canada Thistle (Cirsium arvense)

Canada Thistle flowers.

Canada Thistle (Cirsium arvense)

Canada Thistle (Cirsium arvense)

Closer views of Canada Thistle flower heads.

Canada Thistle (Cirsium arvense)

Canada Thistle (Cirsium arvense)

Side view of a Canada Thistle flower head.

Canada Thistle (Cirsium arvense)

Sometimes the flowers are white.

Canada Thistle (Cirsium arvense)

Canada Thistle leaf, upper side.

Canada Thistle (Cirsium arvense)

Canada Thistle leaf, underside.

Canada Thistle (Cirsium arvense)

Canada Thistle plant.

Canada Thistle (Cirsium arvense)

Canada Thistle (Cirsium arvense)

A dense field of Canada Thistles. This species can be quite invasive!! This is in July when the plants are going to seed.

Canada Thistle (Cirsium arvense)

Canada Thistle going to seed.

Canada Thistle (Cirsium arvense)

Canada Thistle (Cirsium arvense)

Canada Thistle seed heads in the mroning after a very heavy dew.


Range map for Canada Thistle (Cirsium arvense)

PLEASE NOTE: A coloured Province or State means this species occurs somewhere in that Province/State.
The entire Province/State is coloured, regardless of where in that Province/State it occurs.

(Range map provided courtesy of the USDA website and is displayed here in accordance with their Policies)