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CEANOTHUS arboreus 'Trewithen Blue'
Commonly known as Catalina ceanothus, Catalina mountain lilac
Largest blue
Further Reading....
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EvergreenOval to rounded dark-green leaves to 10cm (4in) long.
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BlueMid-blue
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Height6m (20ft)
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Spread8m (26ft)
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Tall ShrubVigorous, spreading shrub or small tree
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Hardy - average winterHardy through most of the UK apart from inland valleys, at altitude and central/northerly locations. May suffer foliage damage and stem dieback in harsh winters in cold gardens. Plant can withstand temperatures down to -10°C (14°F)
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Full sunWith shelter from cold winds. Most do well trained against a wall.
CEANOTHUS arboreus 'Trewithen Blue'
- Details
- Mature Size
- Tips and Advice
- Goes Well With
- Planting Combinations
- Other Suggestions
- See Also...
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Additional FeaturesGood to knowWildlife plant - insectsPests & Diseaseshoney fungus.Place of originNative to Catalina Islands, California, USA. This selection bred at Trewithen Gardens, Grampound, Cornwall, UK
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Flower ShapePaniclesLarge, pyramidal, terminal and lateral panicles to 12cm (4¾in) long
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Garden Location/ConditionsCoastal / windsweptSuitable for open site, slightly back from the sea
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HardinessFully hardy
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Leaf marginSerrulate
(see photos above) -
Leaf shapeOblong
(see photos above) -
Pruning groupPruning group 5Suitable for: Evergreen shrubs that require minimal pruning.
Action: Trim or lightly cut back shoots that spoil symmetry. Deadhead regularly.
When: Annually after flowering.
RHS group 8 -
Scented PlantsScented flowers
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Seasonal InterestSpring
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Soil ConditionsFertile well drained soilFree draining sandy soil
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WildlifeBee friendlyButterfly friendlyRabbit Resistant
Jan
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Ceanothus - Growing Guide
6m (20ft)
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8m (26ft) |
Useful extras...

Fertilisers & Feeds - Vitax
Q4 Pelleted Fertiliser
A useful fertiliser suitable for use on a wide variety of plants. Q4 provides all the nutrients and trace elements essential for vigorous growth, abundant flowering and ripening of fruit.
3 options from £6.00

Fertilisers & Feeds - Empathy
Rootgrow mycorrhizal fungi
Recommended by the RHS. Contains Rootgrow™ mycorrhizal fungi. Suitable for all trees and shrubs (except rhododendrons, azaleas, heathers, cranberries and blueberries)
2 options from £6.00

Fertilisers & Feeds - Empathy
All-purpose Seaweed Stimulant
All-purpose organic concentrated seaweed feed that is a ready to use, derived from sustainable harvested kelp, that can be used on all outdoor and indoor plants, except acid loving plants.
Perfect used in conjunction with Rootgrow™.
Only £7.50

Garden Goodies
Slate Plant Labels
These wonderfully tactile natural slate plant labels are hand made in Cornwall and come with a chalk pen.
Just stick them in your pot or border. Pack of 6.
Only £10.20

Garden Goodies
Slate Tie-on Plant Labels
Hand made in Cornwall, these delightful natural slate labels are perfect for pots.
Comes with chalk pen. Pack of 5
Only £10.20

Garden Goodies
Sisal Twine
2ply sisal garden twine - 250 grams
Only £4.50