Drought-tolerant ceanothus

Credit: By Peter Symcox

Personally, I have long felt that water, for drinking or for the garden, would be in short supply, not only in this part of the world but throughout the entire planet. Consequently, I have repeatedly propounded the need to consider the water-wise garden – that is, a garden that can be reasonably managed in times of stress. Thus, in this and future columns I shall be placing the accent on those plants and shrubs which perform well even when they receive little or no water.

One such shrub is Ceanothus, or California lilac. This is a genus of about 55 deciduous shrubs – some (rarely) grow to become small trees. Mostly from North America, they are also found in the eastern U.S. and Mexico. They are tolerant of dry conditions – as a matter of fact, too much water in the warm summer months will cause many of the species to die. So, when the rain ceases, and the weather is hot and dry, do not despair, for ceanothus will survive very happily. They all grow in fertile, well-drained soil, are tolerant of lime, but will certainly show signs of chlorosis if they are planted in a bed that is too shallow with a soil too alkaline.

As for flowers, they are covered with panicles of light to dark blue or purple, lilac pink or white. There are many species to choose from. I had planted several specimens of C. gloriosus at the edge of my rock-garden wall, from where they spread and cascaded down in a glorious heap of colour, blending marvellously with the Alyssum ‘Golden Basket’ below (a chance seedling) which had decided to interweave its stems up and through to the shrub at the top of the wall. This particular specimen is ideal for a ground cover; it reaches approximately 30 centimetres and can spread to a width of three metres or more. Salt spray from the sea seems not to bother it, and provided it is not too buffeted by strong winds, it survives extremely well.

There are many others to choose from. C. arboreus, with its mid-blue flowers, can reach a height of six metres, and a width of some seven metres. ‘C.A.T. Johnson’ has rich blue flowers from summer to autumn, with a height and width of approximately 2.5 metres. C. ‘Concha’ is particularly attractive, with its reddish-purple buds and dark-blue flowers. Whichever you choose, they are certain to do well in this west-coast climate. They are completely drought tolerant in midsummer, so you need not worry when the soil is dry; just remember those windswept, scrubby hillsides of coastal California!