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Annual Biennial

Cosmos bipinnatus 'Rubenza'
  • RHS AGM
  • RHS Plants for pollinators

cosmea 'Rubenza'

'Rubenza' is a half-hardy annual to 75cm in height with divided, ferny foliage and large deep red, velvety flowers. These fade with age to a warm pink, giving a two tone effect

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Size
Ultimate height
0.5–1 metres
Time to ultimate height
1 year
Ultimate spread
0.1–0.5 metres
Growing conditions
Chalk
Clay
Loam
Sand
Moisture
Moist but well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Red Yellow Green
Autumn Red Yellow Green
Winter
Position
  • Full sun
Aspect

South–facing or West–facing or East–facing

Exposure
Sheltered
Hardiness
H3
Botanical details
Family
Asteraceae
Native to GB / Ireland
No
Foliage
Deciduous
Habit
Columnar upright
Genus

Cosmos can be annuals or perennials with simple or pinnately divided leaves and large, long-stalked daisy-like flowers in summer

Name status

Accepted

How to grow

Cultivation

Grow in moist, but well-drained soil in full sun. Suited to annual or cut-flower borders or as a summer infill

Propagation

See sowing seeds indoors

Suggested planting locations and garden types
  • Cottage and informal garden
  • Patio and container plants
  • Wildlife gardens
  • Cut flowers
  • Flower borders and beds
Pruning

Deadhead to prolong the flowering season

Pests

May be susceptible to aphids and slugs

Diseases

May be susceptible to grey moulds

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