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Annual BiennialSynonym

Carduus marianus

milk thistle

S. marianum is a robust biennial forming a rosette of large, spiny dark green leaves with prominent white veins, and with purple flower-heads with spiny bracts, in the second year

Other common names
blessed Mary's thistle
blessed thistle
see moreholy thistle
lady's thistle
leaves of Mary
Mary's thistle
Our Lady's milk thistle
Our Lady's thistle
St Mary's thistle
lady's milk [3]
Synonyms
Carduus marianus
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Size
Ultimate height
1–1.5 metres
Time to ultimate height
1–2 years
Ultimate spread
0.5–1 metres
Growing conditions
Loam
Sand
Moisture
Well–drained
pH
Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green White
Summer Purple Green White
Autumn Green White
Winter
Position
  • Full sun
Aspect

South–facing or West–facing

Exposure
Exposed or Sheltered
Hardiness
H4
Botanical details
Family
Asteraceae
Native to the UK
No
Foliage
Deciduous
Habit
Columnar upright
Genus

Silybum are large annuals and biennials, with basal rosettes of large, lobed leaves and thistle-like purple flower-heads with spiny bracts in summer

Name status

Correct

Plant range
Mediterranean, SW Europe to Afghanistan

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How to grow

Cultivation

Grow in poor to medium fertile, well-drained, neutral to slightly alkaline soil in full sun. Protect from excess winter wet

Propagation

Propagate by seed sown in late spring or early summer

Suggested planting locations and garden types
  • City and courtyard gardens
  • Mediterranean climate plants
  • Architectural
  • Cottage and informal garden
  • Flower borders and beds
Pruning

No regular pruning required, but flower stems may be removed to keep foliage effect

Pests

Generally pest free

Diseases

Generally disease free

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