Symphyotrichum lateriflorum var. horizontale

RHS Plant Profile

horizontal calico aster

Other common names

aster 'Horizontalis'

Synonyms

Aster lateriflorus 'Horizontalis'
Aster lateriflorus var. horizontalis

Herbaceous Perennial

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'Horizontalis' is a compact herbaceous perennial with small, narrow leaves and wide-spreading branched sprays bearing tiny white-rayed flowers with reddish centres

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

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

Growing Conditions

Chalk Loam Sand

Moisture: Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–facing or West–facing or East–facing
Exposure: Exposed
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: Bushy
Genus: Symphyotrichum includes around 90 species of annuals, biennials and perennials, mostly spread through the Americas, that were formerly included within the genus Aster. Leaves are simple, lance-shaped and entire, but it is their daisy-like flowerheads that they are grown for; central disc florets are typically yellow, surrounded by strap-shaped ray florets in shades of pink, blue, purple or white
Name Status: Correct
Plant Range: N America

How to Grow

Cultivation

Grow in moderately fertile, well-drained soil in open sunny position; may need staking

Propagation

Propagate by division in spring

Suggested planting locations and garden types

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

Pruning

Cut back in late autumn

Pests

Generally pest-free

Diseases

Asters may suffer Verticillium wilt, powdery mildews and grey moulds