Details of...
Scientific Name: Cirsium arvense
Pronunciation: SUR-see-um ar-VEN-see
Common Name: Canada thistle
Family Name: Asteraceae
Plant Type: Invasive plant, Weed (horticultural)
Key ID Features: Leaves simple and pinnate with spines on margins; stems are spineless; flowers pink to violet, tubular composed of many small, narrow, upright petals.
Course(s): HORT 1155, Level 2 Apprenticeship

Habit: Stiffly upright
Form: Oval - vertical
Texture: Medium
Mature Size:
Height:0.7 - 1.3m
Spread:1.0 - 1.5m
Growth Rate:Fast
Origin: B.C. east of Cascades, B.C. west of Cascades, Canada - central, U.S. - southwest
Hardiness Rating: Zone 4: (-34 to -29 C)
Exposure: Full sun
Soil/ Growing Medium: Rocky or gravelly or dry
Water Use: Moderate
Landscape Uses: Attract birds, Wildlife food
Additional Info: Google. Noxious weed. Compare to C. vulgare.
Canada thistle
Leaf Morphology: Glossary
Form: Lobed, Simple
Arrangement: Alternate
Texture/ Venation: Prickly
Surfaces: Pubescent
Leaf(let) Terms:
Shapes: Oblong
Apices: Acuminate
Bases: Decurrent
Margins: Pectinate, Pinnately lobed, Spinose

Inflorescence Type: Head (capitulum)
Flower Morphology:Flowers perfect
Corolla Shape:Tubular
Ovary Position:Inferior
Colour (petals): Violet, Pink, Purple
Flower Scent: None
Flower Time at Peak: Jun, Jul, Aug

Fruit Type: Achene
Fruit Colour: Brown
Fruiting Time: Aug, Sep

Bark or Stem Colour:
Organ Modifications: Prickles, Rhizomes

Propagation: Seed, Division - below ground parts
(WDY) WeeDY location
Location Map

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