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Annual Biennial

Helianthus annuus 'Red Sun'
  • RHS Plants for pollinators

sunflower 'Red Sun'

A fast-growing annual with broad, oval to heart-shaped, roughly hairy leaves. In summer, it bears huge singular flowers with velvety petals of dark bronze and deep dark centres. The flowers attract bees and the seeds that follow provide food for finches

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Size
Ultimate height
1.5–2.5 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
Neutral, Alkaline
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Bronze Orange Green
Autumn Bronze Orange Green
Winter
Position
  • Full sun
Aspect

South–facing or West–facing

Exposure
Sheltered
Hardiness
H4
Botanical details
Family
Asteraceae
Native to GB / Ireland
No
Foliage
Deciduous
Habit
Columnar upright
Genus

Helianthus can be tall, erect annuals, tuberous or rhizomatous perennials, with coarse simple leaves and large daisy-like flower-heads

Name status

Unresolved

How to grow

Cultivation

Grow in a moderately fertile, humus-rich, moist but well-drained, neutral to alkaline soil in full sun. Will flower best in a long, hot summer. May need a cane to support the weight of the bloom and grow tall

Propagation

Propagate by seed or division. Divide established clumps every 2-4 years to both increase plants and retain vigour. See sowing seeds indoors for further advice

Suggested planting locations and garden types
  • Wildlife gardens
  • Cottage and informal garden
  • Flower borders and beds
  • Cut flowers
  • Wall side borders
Pruning

Cut back old stems after flowering as they die down for the winter

Pests

May be susceptible to slugs and snails

Diseases

May be susceptible to Powdery mildews and sclerotinia diseases

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