Not the plant you're looking for? Search over 300,000 plants
Annual Biennial

Cosmos bipinnatus 'Sweet Sixteen'
  • RHS Plants for pollinators

cosmea 'Sweet Sixteen'

A compact, strong and sturdy half-hardy annual with feathery green foliage and single, soft pink to white flowers with darker pink edging, a central double frill of narrower petals and yellow centres which appear from July through to October. These make good cut flowers and are very beneficial to pollinating insects

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 Pink White Green
Autumn Pink White Green
Winter
Position
  • Full sun
Aspect

East–facing or South–facing or West–facing

Exposure
Sheltered
Hardiness
H3
Botanical details
Family
Asteraceae
Native to the UK
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
  • City and courtyard gardens
  • 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

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.