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Herbaceous Perennial

Cosmos atrosanguineus

chocolate cosmos

A spreading tuberous perennial, with pinnately divided leaves and bowl-shaped, chocolate-scented, maroon-crimson flower-heads in late summer

Other common names
black cosmos
black dahlia
Synonyms
Cosmos atrosanguineus 'Chocolate'
Cosmos diversifolius atrosanguineus
see moreBidens atrosanguinea

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Size
Ultimate height
0.5–1 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Chalk
Loam
Sand
Moisture
Moist but well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Red Green
Autumn Green
Winter
Position
  • Full sun
Aspect

South–facing or West–facing or East–facing

Exposure
Exposed or Sheltered
Hardiness
H3
Botanical details
Family
Asteraceae
Native to GB / Ireland
No
Foliage
Deciduous
Habit
Spreading branched
Genus

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

Name status

Correct

Plant range
Mexico

How to grow

Cultivation

Grow in a moderately fertile, moist but well-drained soil in full sun. Mulch in autumn; in cold areas lift tubers before first frosts and keep frost-free over winter.

Propagation

See sowing seeds indoors

Suggested planting locations and garden types
  • City and courtyard gardens
  • Cottage and informal garden
  • Cut flowers
  • Flower borders and beds
Pruning

Deadhead to prolong flowering

Pests

Generally pest-free

Diseases

May be susceptible to foot rot and grey moulds

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