• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

Helianthus annuus

common sunflower

  • Other common names common sunflower
    comb flower

    golden
    golden flower of Peru
    St Bartholomew's star

    see more
  • Family Asteraceae

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

  • Details H. annuus is a tall, fast-growing annual with broad, oval to heart-shaped, roughly hairy leaves 10-40cm long. In summer it bears huge flowers up to 30cm across with bright yellow petals and dark brownish or purplish centres. The flowers attract bees and the seeds that follow provide food for finches

Characteristics

  • Foliage Deciduous

  • Habit Columnar/Upright

  • Hardiness

    Hardiness ratings

    All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

    • H1a - Under glass all year (>15C)
    • H1b - Can be grown outside in the summer (10 - 15)
    • H1c - Can be grown outside in the summer (5 - 10)
    • H2 - Tolerant of low temperatures, but not surviving being frozen (1 to 5)
    • H3 - Hardy in coastal and relatively mild parts of the UK (-5 to 1)
    • H4 - Hardy through most of the UK (-10 to -5)
    • H5 - Hardy in most places throughout the UK even in severe winters (-15 to -10)
    • H6 - Hardy in all of UK and northern Europe (-20 to -15)
    • H7 - Hardy in the severest European continental climates (< -20)

    H4

Colour

Sunlight

  • Full Sun

  • Aspect West-facing or South-facing

  • Exposure Sheltered

Soil

  • Sand

    Sand

  • Loam

    Loam

  • Clay

    Clay

  • Chalk

    Chalk

  • MoistureMoist but well-drained

  • SoilSand, Loam, Clay, Chalk

  • pHAlkaline, Neutral

Size

  • Ultimate height 2.5-4 metres

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 1 year

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 support

Propagation Propagate by seed sown in-situ or in a pots or modules in spring

Suggested planting locations and garden types Flower borders and beds Cut Flowers Wall-side Borders Wildlife Gardens Cottage & Informal Garden

How to care

Pruning No pruning needed

Pests Can get slugs and snails

Diseases May be affected by powdery mildews and sclerotinia diseases

Did you find the information you were looking for?

RHS members can get exclusive individual advice from the RHS Gardening Advice team.

Join the RHS now

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.