Ceanothus bear masses of gorgeous blue flowers in May and June, on otherwise fairly humble shrubs. Also known as California lilacs, which tells us their country of origin, ceanothus shrubs come in a range of sizes to suit most gardens. Evergreen varieties tend to be slightly less hardy than deciduous types, but can be grown as free-standing shrubs or small trees in sheltered gardens. The prostrate forms of ceanothus work well as ground cover. Pollinating insects love the Liquorice Allsort blue flowers as much as we do.
How to grow ceanothus
Grow ceanothus in moist but well-drained soil in full sun in a sheltered spot. Trim back after flowering each year, to maintain its shape.
More on growing ceanothus:
Follow our detailed guide to growing ceanothus, below.
Take into account the Californian origins of Ceanothus and choose a spot in full sun. Soil should be moist but well-drained. In more exposed gardens, Ceanothus will benefit from being planted near a south- or west-facing wall that will give some shelter from cold winds and winter frost. If you can’t provide shelter, choose one of the hardier, deciduous varieties.
Plant ceanothus in the autumn when the soil is still warm. Dig a generous hole and add handfuls of grit so the soil is very well drained.
Caring for ceanothus
Trim ceanothus annually to keep plants bushy and leafy. Cut out dead wood in spring and trim side-shoots after flowering. If you inherit a ceanothus that has outgrown its position or become slightly unshapely, don’t try to prune it back hard as they don’t recover successfully.
The accepted method of propagation for evergreen ceanothus is to take semi-ripe cuttings from the current season’s growth, after flowering, any time up until the autumn. For deciduous varieties, take softwood cuttings from new growth in spring.
Growing ceanothus: problem solving
Ceanothus is a relatively pest and disease free shrub and should thrive, provided the planting conditions are right. It is on the list of shrubs that can succumb to honey fungus, and in some case, it can be prone to scale insects.
Ceanothus varieties to try
- Ceanothus ‘Concha’ – an evergreen cultivar with arching branches and a dense growth habit, flowering in April and May. The Royal Horticultural Society has given it the prestigious Award of Garden Merit (AGM).
- Ceanothus ‘Cynthia Postan’ – hardy and evergreen, this is perfect for growing in a mixed border. It can be also be trained against a wall or fence or grown as a small standard shrub.
- Ceanothus thyrsiflorus var. repens – one of the hardiest varieties, this is a low-growing evergreen, forming a natural mounded shape. It looks good at the front of a mixed border. It holds the RHS AGM.
- Ceanothus ‘Blue Cushion’ – a compact, evergreen variety with small, oblong, dark green leaves. The flowers are a darker blue than other varieties, and appear in late spring. In very cold winters, plants may need some protection from frost.
- Ceanothus ‘Autumnal Blue’ – a taller, late flowering variety, growing to 3m in height. Another variety with the RHS AGM.
- Ceanothus ‘Gloire de Versailles’ – a medium sized, deciduous variety, that can tolerate a more exposed planting position. RHS AGM.