Cirsium heterophyllum

RHS Plant Profile

melancholy thistle

Other common names

ysgallen fwyth

Synonyms

Cirsium helenioides
Carduus heterophyllus
Carduus ambiguus

Herbaceous Perennial

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A clump-forming, spreading perennial up to 1.2m tall. The lance-shaped, green leaves have softly-spiny edges and white-felted undersides. In summer, purple-pink spherical flower heads 3-5cm across are borne on erect, woolly-textured stems

Position

Full sun, Partial shade

Soil Types

Chalk, Loam, Sand

Max Height

1-1.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 1-1.5 metres

Growing Conditions

Chalk Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: North–facing or East–facing or South–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H7

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Asteraceae
Native to GB/Ireland: Yes
Foliage: Deciduous
Habit: Clump forming
Genus: Cirsium may be biennials or perennials with spiny leaves and typical thistle-type flower-heads
Name Status: Correct
Plant Range: Europe, Russia

How to Grow

Cultivation

Grow in a moist but well-drained soil in full sun; can tolerate some dryness and partial shade

Propagation

Propagate by seed sown in pots in a cold frame in spring or by division in spring

Suggested planting locations and garden types

Cottage and informal garden
Wildlife gardens
Wildflower meadow
Cut flowers
Flower borders and beds

Pruning

If self-seeding is a problem then cut back hard after flowering

Pests

Generally pest-free

Diseases

Generally disease-free but may be susceptible to powdery mildews