Achillea millefolium 'Cassis'

RHS Plant Profile

yarrow 'Cassis'

Herbaceous Perennial

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A clump-forming perennial producing a mound of finely-divided, deep green foliage and branching, upright stems to 60cm tall bearing flattened clusters of small, white-centred, deep cherry-red flowers from summer into autumn

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

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

Growing Conditions

Chalk Loam Sand

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

Position

Full sun

Aspect: South–facing or West–facing or East–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: No
Foliage: Deciduous
Habit: Clump forming
Genus: Achillea can be mat-forming or upright perennials, mostly herbaceous, with sometimes aromatic, pinnately divided or simple and toothed leaves and flattened clusters of small, daisy-like flower-heads
Name Status: Accepted

How to Grow

Cultivation

Grow in an open, sunny position in well-drained soil

Propagation

Propagate by division in spring

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Gravel garden
Prairie planting
Wildlife gardens
Cut flowers
Flower borders and beds

Pruning

Cut back untidy foliage in spring; deadheading may encourage repeat flowering in the summer

Pests

May be susceptible to aphids

Diseases

May be susceptible to powdery mildews