• 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

Thuja plicata

western red cedar

  • Other common names western red cedar
    British Columbia cedar

    Californian white cedar
    giant arbor-vitae
    Nootka Sound arbor-vitae
    western arbor-vitae
    yellow cypress

    see more
  • Synonyms Thuja gigantea
    Thuja lobbii

  • Family Cupressaceae

  • Genus Thuja are fast-growing evergreen trees of narrowly conical habit, with flat sprays of tiny, aromatic, scale-like leaves and small knobbly cones

  • Details T. plicata is a large, evergreen, narrowly-pyramidal tree reaching an ultimate height of up to 35m. Aromatic, glossy, scale-like, sharply-pointed leaves are held in large drooping sprays on spreading branches that curve upwards at the end. Cones are egg-shaped and around 1.3cm long

  • Plant range W North America

Characteristics

  • Foliage Evergreen

  • Habit Columnar/Upright

  • Fragrance Foliage

  • Toxicity Contact with foliage may irritate the skin. Wear gloves and other protective equipment when handling

  • 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)

    H6

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Chalk

  • Clay

    Clay

  • Loam

    Loam

  • Sand

    Sand

  • MoistureMoist but well-drained, Well-drained

  • SoilChalk, Clay, Loam, Sand

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height Higher than 12 metres

  • Ultimate spread wider than 8 metres

  • Time to ultimate height 10-20 years

How to grow

Cultivation Grows best in moist but well-drained soil. Protect from drying winds especially when young. Suitable for hedging or screening

Propagation Propagate by semi-hardwood cuttings

Suggested planting locations and garden types Hedging & Screens Low Maintenance Architectural

How to care

Pruning None required, unless grown as a hedge

Pests May be attacked by scale insects and conifer aphids

Diseases May be subject to coryneum canker (see Conifers: brown patches)

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