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Herbaceous Perennial

Cosmos atrosanguineus

chocolate cosmos

C. atrosanguineus is 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 the UK
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

Propagate by taking basal cuttings in early spring and providing bottom heat

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 suffer from foot rot and grey moulds

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