The photo is of three Canada thistle plants joined together by a rhizome.

Canada thistle - Cirsium arvense

Cirsium arvense

Asteraceae (Aster family)

 

MI Status

Non-Native

Life cycle

Colony-forming perennial.

Leaves

Leaves are alternate, sessile, oblong to lanceolate, irregularly lobed with spiny margins.  The base of each leaf surrounds the plant stem. 

Stems

The stems are grooved, erect, smooth to slightly hairy, and they branch at the apex.  

Flowers and fruit

The flower heads are composed of pink to purple disk flowers, surrounded by spineless bracts. Canada thistle is dioecious with male and female flowers on separate plants. 

Reproduction

Seeds, creeping roots, and rhizomes

 

The photo is of a Canada thistle plant in a field of soybeans.
Canada thistle plant
The photo is a close up of a Canada thistle leave.
Canada thistle leaves
The photo is of a Canada thistle flower and a seed head.
Canada thistle flower and seedhead
The photo is of Canada thistle plants joined by a rhizome.
Canada thistle rhizome

 

 

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  • msu plant & pest diagnostics,
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