Scientific name: Onopordum acanthium
Synonym: Onopordon acanthium
Family: ASTERACEAE
Common names: “Scotch thistle” “cotton thistle” “Argentine thistle” “giant thistle” “musk thistle” “Queen Mary’s thistle” “silver thistle” “star thistle” “thistle-upon-thistle”
Plant Type: Evergreen biennial
Conditions:
Zone: 6-9
Light: Full sun
Exposure: Exposed or sheltered
Soil: Fertile – poorer sites, neutral – slightly acidic best (some sources say slightly alkaline) prefers less clay
Moisture: Well drained
Aesthetic:
Plant Size: H 9′ W 3′
Leaf and Stem shape: Oblong, spiny, cobwebby grey leaves
Flower: Rounded, thistle-like purple flower heads in summer of second year
Pruning: Minimal
Maintenance: Transplant seedlings when young in fall, can cut out flowers to prevent seedlings
Landscape use: Not in a narrow bed or near pathways, gravel garden, cottage, wildflower meadow
Propagate: By seed, self seeds about
Pests & Disease: None in Victoria
Comments: Prickly and painful, on BC invasive plant list
