Californian lilacs bring vibrant colour to gardens at this time of year.
If you see a blast of blue in gardens at this time it’s almost certainly a Californian Lilac. Unrelated to the traditional lilac or Syringa, the value of Californian lilac or ceanothus is becoming more widely appreciated. Right now no other shrub offers such a rich and exotic splash of colour, powerfully contrasting with the razzle-dazzle of late tulips and early perennials. As the name suggests these evergreen, semi-evergreen and deciduous plants come from the dry, sunny hills, coastal ranges and forest clearings of California, but also into the Rocky Mountains, Oregon and British Columbia.
Of the 50-plus species around 10 are grown in gardens, which along with various hybrids between them has spawned 50 or so varieties. The larger number of evergreen and semi-evergreen forms with glossy, dark green foliage blossom in spring and early summer, the handful of paler green leaved deciduous species in summer. Although predominantly in shades of blue, a few varieties produce white or even pink blooms. While individual flowers are tiny, they are massed into dense bobble-headed clusters or more open sprays and are attractive to bees and other pollinators. Variegated forms have also arisen with creamy yellow to white variegation.
Plants vary in height and habit, the largest achieving between 3m (10ft) or more high and wide, while some are smaller, others spreading, making them useful for cascading over larger retaining walls. Plants will maintain a tighter growth habit if regularly clipped after flowering. Plants cut back hard should recover when producing new shoots, with deciduous varieties than evergreen and younger, rather than older proving more amenable.
Ceanothus prefer well-drained soil, and are particularly useful for chalky soil and need full sun. They make good wall shrubs, especially for a south-facing position, where the evergreen species flowering now will be more protected from cold, winter winds. The deciduous species are generally hardier.