• 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

Petunia Amethyst Halo (Sweetunia Series)

petunia [Amethyst Halo]

© RHS
  • Other common names petunia [Amethyst Halo]

  • Family Solanaceae

  • Genus Petunia can be annuals or perennials, with simple leaves and large, solitary, trumpet-shaped flowers in the upper leaf axils from late spring to autumn

  • Details

    amethyst halo is a compact, bushy, semi-trailing annual bearing a profusion of purple flowers edged with white from early summer into autumn

Characteristics

  • Foliage Deciduous

  • Habit Trailing

  • 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)

    H2

Colour

Sunlight

  • Full Sun

  • Aspect South-facing or West-facing

  • Exposure Sheltered

Soil

  • Sand

    Sand

  • Loam

    Loam

  • MoistureWell-drained

  • SoilSand, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 0.1-0.5 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 1 year

How to grow

Cultivation Overwinter young plants under glass in frost free conditions and plant out after frosts have passed. Grow in light, well-drained soil in full sun, with shelter from drying winds

Propagation Propagate by softwood cuttings in summer

Suggested planting locations and garden types Banks and Slopes Flower borders and beds Garden Edging City & Courtyard Gardens Coastal Cottage & Informal Garden Gravel Garden Patio & Container Plants

How to care

Pruning Deadhead regularly to prolong flowering

Pests Aphids and slugs may be a problem

Diseases May be subject to fungal foot rot and a virus

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