• AGM plants

    AGM plants have been through a rigourous 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

Ceanothus 'Concha'

Californian lilac 'Concha'

AGM plants

AGM plants have been through a rigourous 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
Californian lilac 'Concha'

© � RHS 1999

  • Other common names Californian lilac 'Concha'

  • Synonyms Ceanothus azureus 'Concha'

  • Genus Ceanothus can be evergreen or deciduous shrubs or small trees, with simple leaves and small blue, pink or white flowers in profuse axillary or terminal clusters. They are fast-growing but may be short-lived

  • Family Rhamnaceae / Rhamnaceae

  • Species 'Concha' is an evergreen shrub of dense habit, to 3m in height and width, with arching branches bearing narrow, dark green leaves and profuse clusters of deep blue flowers in late spring

Characteristics

  • Foliage Evergreen

  • 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)
    Old hardiness ratings

    While we update our systems with the new hardiness ratings you may still see old hardiness ratings in your search results. These are denoted as 'Old'.

    • H1 - Requires heated glass
    • H2 - Requires unheated glass
    • H3 - Hardy outside in some regions of the UK
    • H4 - Hardy throughout the UK
    • H1 + H3 - Requires heated glass but may be grown outside in summer

    For full details of the hardiness ratings see

    see more

    H4

Colour

Sunlight

  • Full Sun

  • Aspect South-facing or East-facing or West-facing

  • Exposure Sheltered

Soil

  • Chalk

    Loam

  • Chalk

    Clay

  • Chalk

    Sand

  • MoistureWell-drained, Moist but well-drained

  • SoilLoam, Clay, Sand

  • pHAlkaline, Neutral

Size

  • Ultimate height

    2.5-4 metres

  • Ultimate spread

    2.5-4 metres

  • Time to ultimate height

    10-20 years

How to grow

Cultivation Grow in well-drained soil in a sheltered position in full sun

Propagation Propagate by semi-hardwood cuttings

Suggested planting locations and garden types Wall-side Borders City & Courtyard Gardens

How to care

Pruning Pruning group 8

Pests Can get scale insects

Diseases May be affected by honey fungus and Phytophthora root disease

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