• 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

Ageratum houstonianum 'Blue Horizon'

Mexican paintbrush 'Blue Horizon'

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
  • Other common names Mexican paintbrush 'Blue Horizon'

  • Family Asteraceae

  • Genus Ageratum can be annuals, perennials or shrubs, usually bushy in habit, with simple ovate leaves and small fluffy blue, pink or white flower-heads in summer and autumn

  • Details 'Blue Horizon' is a mound-forming annual with long-stemmed violet-blue flower-heads. Good for cutting

Characteristics

  • Foliage Deciduous

  • Habit Bushy

  • 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

  • Chalk

    Chalk

  • Clay

    Clay

  • Loam

    Loam

  • Sand

    Sand

  • MoistureMoist but well-drained

  • SoilChalk, Clay, Loam, Sand

  • 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 This genus is ideal edging for bedding schemes; bearing weather-resistant flowers on young plants. To prolong flowering, keep soil or growing media moist.

Propagation Propagate by seed

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

How to care

Pruning No pruning required

Pests Generally pest free

Diseases Generally disease free

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