Californian lilac 'Puget Blue'

Sun

Full sun; tolerates light shade, but flowers less freely.

Water

Water regularly during establishment, allowing the soil surface to dry between waterings. Once established, it tolerates drought and usually needs little extra water; avoid frequent summer irrigation.

Soil

Well-drained, moderately fertile soil, from slightly acidic to alkaline. Avoid waterlogged clay and very chalky soils.

Height

8-12 ft (2.4-3.7 m)

Spread

8-12 ft (2.4-3.7 m)

Flowers

Dense clusters of deep blue flowers in late spring to early summer; usually May-June in the Northern Hemisphere and October-November in Australia.

Foliage

Small, evergreen, dark green leaves with a deeply impressed, puckered surface.

Growth

Fast when young, slowing as it matures.

Care needed

Low

• Pollinators
• Drought tolerant
• Heat tolerant
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.6 ft (0.5 m)

2. After 1 year

   3 ft (1 m)

3. After 2 years

   5 ft (1.5 m)

4. After 3 years

   7 ft (2 m)

5. After 5 years

   10 ft (3.1 m)

   full size

About 5 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Plant in spring in colder areas, or autumn where winters are mild, leaving room for its mature width.
• Water deeply during the first growing season, then reduce watering as roots establish.
• Avoid routine feeding, especially high-nitrogen lawn fertiliser near the roots.
• Apply a thin mulch over the root area, keeping it clear of the stem base.
• Choose a sheltered site away from frost pockets, and avoid disturbing established roots.

Pruning. Immediately after flowering, lightly shorten long shoots within the leafy growth to keep the shrub dense. Remove dead or damaged branches, but do not cut hard into bare old wood, which often fails to regrow.

Early spring

Check for frost damage; wait until growth resumes before removing clearly dead shoots.

Spring

Plant in colder districts and water thoroughly while the roots establish.

Late spring

Enjoy the flowers and check young shoots for aphids.

Early summer

After flowering, lightly trim wayward shoots without cutting into bare wood.

Summer

Water young plants during dry spells; keep established plants out of frequently irrigated beds.

Autumn

Plant in mild-winter districts where soil drains freely; avoid pruning before winter.

• Use as an informal evergreen screen, allowing enough space to avoid repeated hard clipping.
• Train against a sunny, sheltered wall, tying in young branches while they are flexible.
• Place at the back of a sunny border with lavender, rock roses and ornamental grasses.
• Use as a large flowering anchor in a gravel garden or mild coastal garden.

Garden styles it suits: Mediterranean, Coastal, Dry gravel garden, English country, Pollinator garden and Pacific Northwest woodland.

Plant it with: Lavender, Rock rose, Rosemary, Santolina, Bearded iris and Blue oat grass.

Wildlife: The flowers attract bees and other pollinating insects. Dense evergreen branches provide shelter for small birds.

• Root rot and sudden collapse in wet soil: improve drainage before planting and avoid frequent irrigation; replace badly affected plants in a better-drained position.
• Frost and cold-wind damage: choose a sheltered site and remove dead growth in spring once the extent of damage is clear.
• Yellow leaves on strongly alkaline soil: check drainage and soil conditions; use an iron treatment labelled for lime-induced chlorosis if needed.
• Scale insects or aphids: inspect stems and young growth; remove small infestations by hand or with water, and avoid spraying open flowers.

Not known to be toxic to people, cats, dogs or horses. No part is generally recognised as poisonous, although cultivar-specific information is limited; it is not an edible plant.

• Common lilac (Syringa vulgaris)

  Common lilac loses its leaves in winter and has much larger, heart-shaped leaves and strongly scented flower panicles.

• Blueblossom (Ceanothus thyrsiflorus)

  Typical blueblossom has larger, flatter leaves; 'Puget Blue' has notably small leaves with a puckered surface. Named ceanothus cultivars can be difficult to identify without a label.

• Californian lilac 'Gloire de Versailles' (Ceanothus × delilianus 'Gloire de Versailles')

  This deciduous shrub has larger leaves and loose clusters of paler blue flowers in summer and early autumn, rather than the dense spring display of 'Puget Blue'.

The common name Californian lilac refers to its Californian relatives and lilac-like blue flower clusters, although it is not related to true lilacs.

Propagation. Take semi-ripe cuttings from healthy, non-flowering shoots in late summer and root them in a free-draining medium under cover. Seed will not reliably produce plants identical to 'Puget Blue'.

Accepted botanical name

Ceanothus

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.