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Ceanothus arboreus 'Trewithen Blue'
  • RHS AGM

Californian lilac 'Trewithen Blue'

A large vigorous, spreading evergreen shrub to 6m in height, with broadly oval or rounded dark green leaves to 8cm in length, and slightly fragrant, mid-blue flowers in pyramidal panicles to 12cm in length, borne in spring and early summer

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Size
Ultimate height
4–8 metres
Time to ultimate height
5–10 years
Ultimate spread
4–8 metres
Growing conditions
Loam
Sand
Moisture
Well–drained
pH
Alkaline, Neutral, Acid
Colour & scent
StemFlowerFoliageFruit
Spring Blue Green
Summer Blue Green
Autumn Green
Winter Green
Position
  • Full sun
Aspect

West–facing or South–facing

Exposure
Sheltered
Drought resistance
Yes
Hardiness
H4
Botanical details
Family
Rhamnaceae
Native to the UK
No
Foliage
Evergreen
Habit
Bushy
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

Name status

Accepted

How to grow

Cultivation

Grow in fertile, well-drained soil in full sun with shelter from strong, cold winds. Lime tolerant but may become chlorotic on shallow chalk soils. See ceanothus cultivation

Propagation

Propagate by semi-ripe cuttings in mid- to late summer

Suggested planting locations and garden types
  • Architectural
  • City and courtyard gardens
  • Coastal
  • Cottage and informal garden
  • Mediterranean climate plants
  • Wall side borders
  • Climber and wall shrubs
Pruning

Pruning group 8 after flowering or pruning group 13 if wall trained

Pests

May be susceptible to scale insects

Diseases

May be susceptible to honey fungus

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