• 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

Picea pungens (Glauca Group) 'Koster'

Colorado spruce 'Koster'

Colorado spruce 'Koster'

© � RHS

  • Other common names Colorado spruce 'Koster'

  • Synonyms Picea kosteri 'Glauca'
    Picea pungens 'Koster Compacta'

  • Genus Picea are evergreen trees with rigid, needle-like leaves arranged singly all round the shoots, and narrow, leathery-scaled cones borne near the ends of the shoots

  • Family Pinaceae / Pinaceae

  • Species 'Koster' is an evergreen conifer making a medium-sized tree of neat, conical habit, with prickly, vivid silvery-blue foliage

Characteristics

  • Foliage Evergreen

  • Habit Columnar_Upright#Columnar/Upright

Colour

Sunlight

  • Full Sun

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

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Loam

  • Chalk

    Clay

  • Chalk

    Sand

  • MoistureMoist but well-drained

  • SoilLoam, Clay, Sand

  • pHAcid, Neutral

Size

  • Ultimate height

    2.5-4 metres

  • Ultimate spread

    1-1.5 metres

  • Time to ultimate height

    20-50 years

How to grow

Cultivation Grow in moist but well-drained acidic soil. Shelter from cold drying winds

Propagation Propagate by grafting or semi-hardwood cuttings

Suggested planting locations and garden types Low Maintenance Architectural

How to care

Pruning No pruning required

Pests May be attacked by adelgids, aphids and conifer red spider mite

Diseases Generally disease free

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