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Ceanothus 'Trewithen Blue' Tree

Californian Lilac Trees
  • From £75 (inc VAT)

Ceanothus 'Trewithen Blue' is a fantastic evergreen tree with profuse, rich blue summer flowers emerging in clusters from April through to June. Ceanothus, also known as Californian Lilac, are very popular with bees and butterflies due to the mass of flowers that cover them. The evergreen oval foliage provides a dark-green foil for neighbouring plants in summer and substance to the garden in winter.

It can be grown as a a small tree reaching up to 3 metres in height or as a climbing shrub. We offer both single stem and multi stem Ceanothus trees, but they can also be grown as a climbing shrub by training them against a wall if you wish. If you're looking for a patio version, see Ceanothus thyrsiflorus repens.

Ceanothus 'Trewithen Blue' is great for year round interest, with its profuse blue flowers and evergreen foliage. Originating from California, Ceanothus require a well drained soil and sunny situation that is not exposed to drying winds.

AKA Californian lilac, Ceanothus arboreus 'Trewithen Blue'

  • Common name: Californian Lilac tree
  • Latin name: Ceanothus 'Trewithen Blue'
  • Awards: RHS Award of Garden Merit
  • Height and spread in 20 years: 3 x 3 metres
  • Foliage: Dark green & evergreen (spring/summer/autumn/winter)
  • Flowers: Bright blue flowers in spring & summer
  • Soil: Prefers fairly well draining & neutral to alkaline soil
  • Position: Prefers full sun

Planting Advice for Ceanothus Trewithen Blue Trees

Our pot grown Californian Lilac trees can be planted at any time of the year. Choose a sunny position for this species and dig a square hole as deep as the root mass and approximately twice as wide. To help it establish, remove weeds and grass within a metre of the planting hole and sprinkle root grow inside the hole.

Remove the pot, gently loosen the roots and place into the planting hole. Mix 50% of the original soil with 50% compost, fill in the hole and firm around gently. Avoid banking the soil up around the collar of the tree.

We recommend planting single stem Ceanothus trees with a stake and tie. Place the stake at an angle to the tree to avoid penetrating the rootmass and knock in until it is firm. Tie the tree firmly to the stake using a tree tie.

Aftercare of Ceanothus Trewithen Blue Trees

If you’re planting Ceanothus in spring or summer, water well for the first few months. Increase watering if there are extended periods of hot or dry weather. If planting in autumn, you may only need to water a little. Irrigation kits make watering easier.

Keep the area free of competing weeds and grass for the first couple of growing seasons. If your area is prone to rabbits, use a rabbit guard on single stem forms.

Pruning Advice for Ceanothus Trewithen Blue Trees

Ceanothus trees do not require a lot of pruning. Simply remove any dead, diseased or awkwardly placed branches from the tree as and when you see them.

Delivery Costs

*Free delivery promotion excludes mature trees, extra large kits and delivery to Highlands or Islands. Discount applies at checkout.

  Small/medium trees & shrubs

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All other mature trees
Mainland UK ex. Scottish Highlands £8 for any quantity £35 for 1-4 trees From £55 for any quantity
Scottish Highlands & the Islands From £30    
Outside Mainland UK Currently we are unable to deliver outside of Mainland UK

Delivery Times

Next Day Despatch
We will always try to get your plants to you as quickly as possible.  For many of our trees and plants, if you order today we will despatch your order within 24 hours.  We are constantly adding to our range of next day plants, and we do not add a surcharge for this service. Click here to see our next day delivery plants.

Standard Delivery
We have one of the widest range of trees in the UK, and for those plants which we cannot despatch next day we will normally despatch within 4 weeks. The despatch time for different products will be confirmed when products are added to your shopping basket

We will only want to deliver your orders when they are perfect for planting! Depending on the season and how well the plants are growing, we will give our best estimates of the despatch dates for pre-orders.  These dates may vary and by species and while we will always try to deliver within these timeframes if the expected despatch does change then we will notify you by email.

Special Orders
Orders containing pleached or mature trees (trees over 2.5m in height) are delivered within 3 weeks. They require specialist delivery and are grouped geographically. Any customers ordering pleached or mature trees will be contacted and notified of their delivery date.

If your trees are required by a specific date, please let us know as soon as possible; while we can’t offer any guarantees we will always do our best to accommodate you. You can leave instructions in the notes field on the Delivery Page of the Checkout or send us an email at [email protected].

Please note that orders are shipped once all the trees in the order are ready.

Collections are by appointment only at our West Yorkshire-based nursery. If you would like to place an order for collection, please get in touch before placing your order. You will not be charged a delivery cost for a collection and any delivery cost that has been applied will be refunded.

The product table at the bottom of the page gives the forms and sizes available for this variety. Please note, photos are a guideline as all plants are unique. *Pot sizes may vary. Below are definitions of terms:

Supplied Size: Height measured from the top of the pot.

Single Stem tree: Classic tree with one trunk, pruned for a beautiful, natural shape.

Top grafted tree: A height next to this form refers to the length of clear stem, which will not grow taller. Only the head of branches will develop. Ideal for small spaces.

Feathered tree: Branches from the bottom of the trunk all the way up. These branches can be removed if a clear stem is required.

Multi Stem tree: Two or more stems arising from or near ground level, growing from one root system.

Bush: A plant with many stems low down, rather than one clear stem.

Clump: Several plants in one pot that give the appearance of a bushy multi stem tree.

Climber: Naturally climbing plant. Usually delivered running up a cane, ready to position in the garden.

Standard Tree: A more mature tree with an upright clear stem of approximately 1.8m-2.0m (measured from the soil to the lowest branches of the crown). Standards are available in different forms relating to their girth size (circumference of the stem measured 1m above soil level), not height.


Plant Specification Form Size Root type Price Quantity Qty
Ceanothus 'Trewithen Blue' Form: Single stem tree Size: 150-200cm Root type: 10L pot* Ceanothus 'Trewithen Blue' Price £75 (inc VAT)
Single stem tree 150-200cm 10L pot* £75 (inc VAT)
Ceanothus 'Trewithen Blue' Form: Multi-stem Size: 175-225cm Root type: 15L pot* Ceanothus 'Trewithen Blue' Price £90 (inc VAT)
Multi-stem 175-225cm 15L pot* £90 (inc VAT)
Ceanothus 'Trewithen Blue' Form: Multi-stem Size: 200-250cm Root type: 28L pot* Ceanothus 'Trewithen Blue' Price £235 (inc VAT)
Multi-stem 200-250cm 28L pot* £235 (inc VAT)
Total: £0 (VAT Free)