A massive froth of blue flowers anytime from late winter to midspring, whether on a groundcover, a shrub, or a small tree, is probably ceanothus, or California lilac. Each flower is tiny, but on the more spectacular specimens, the plant is covered with them.
The shade of blue depends on the cultivar, and can range from a pale silvery blue, to a soft powdery blue, to the deepest sky blue or a saturated indigo. White-flowering varieties are also available.
In colder climates of England and northern France, where ceanothus has been grown for hundreds of years, it is often trained against south-facing walls. Seduced by its beauty, British horticulturists have been fiddling around with ceanothus and creating hybrids since the first eastern ceanothus seed got there in 1713. California blueblossom seeds made it there in 1837, and many of our other species have followed since then. That's why so many ceanothus varieties originated in Europe and for many years were not available here, even if the parent plant was native to California.
It took California growers until the first quarter of the twentieth century to start collecting ceanothus varieties and selecting cultivars. Here, the native species and cultivars usually prefer well-drained soil, sun to part shade, little or no added water after they are established, and minimal pruning.
Given the glorious range of blues, it's easy to fall in love with the color of a blooming plant in the nursery and then learn about its garden tolerance or eventual size. At most nurseries and native-plant and botanical-garden sales, it can be difficult to choose the appropriate plant based on a short description on a plant label or in a catalog. For most people, the eight pages on ceanothus in the book California Native Plants for the Garden by Bornstein, Fross, and O'Brien provide enough information to help choose one of the popular cultivars.
For more adventuresome gardeners, or those curious about the breadth of choices, a new book offers information on the provenance of each cultivar, as well as detailed descriptions, preferred conditions and uses, hardiness, and a few notes about relative availability.
Entitled Ceanothus, the book was published by Timber Press in 2006 and is a treasure for ceanothus lovers. The first half, written by nurseryman David Fross, offers authoritative horticultural information on about 150 species and cultivars available in the U.S. and British Isles. The second half, written by botanist Dieter Wilken, describes species found in the wild.
Aside from the detailed descriptions of about 150 types of ceanothus and the lovely color photos on every page or two, what I like best about the book are the page of propagation tips and the three-page selection guide. The latter recommends up to a dozen or two ceanothus for each of the following categories: garden tolerant, fast growing, bank covers, ground covers, informal hedges (naturally rounded form), screens, specimens and small trees, small gardens, seashore tolerant, shade tolerant, variegated foliage, summer flowering, large flowering trusses, and white flowers.
© 2008 Tanya Kucak