Without a doubt one of our local rock stars, the venerable California lilac deserves a conspicuous spot in every native garden. From prostrate, tiny-leaved, compact shrubs to small trees, with white to near every possible shade of blue-purple to purple flower imaginable, there is bound to be a match that will fit the gardener's palette. Most species are evergreen, with deep green, glossy leaves.
A versatile, drought-tolerant pollinator plant, species of California lilac attract many important native butterfly, bee, and bird species. Some species can be strongly fragrant. Opinions on levels of deer resistance vary, with some consensus on those types with small, leathery, holly-type leaves. Artificial irrigation tends to encourage softer growth, which is more palatable for deer. California lilacs tend to be sensitive to supplemental watering, with some varieties more tolerant than others. In general, popular cultivars thrive best with infrequent, deep irrigation during the summer months. Depending on habit, Ceanothus can be planted as groundcovers or as screens or hedges, as well as specimen plants that showcase their full, colorful spring glory.
In addition to their distinctive appearance, Ceanothus species, along with only a small handful of other plant genera outside the pea family, or Fabaceae, are nitrogen-fixing. These plants form symbiotic relationships with specific soil bacteria that live in root nodules formed by the plant. These bacteria convert nitrogen gas, N2, into ammonia, NH3, which is further processed to a nitrogen form usable by plants. As one of the most desired, and therefore most limited ecosystem nutrients, this ability gives this classification of plants a strong competitive advantage.
Though the greatest species' diversity by area can be found within California, with well over 50 different species and subspecific types identified, Ceanothus are limited to North America, from Canada to Panama. Unrelated to Syringa, the true lilac genus, it is believed the common name "lilac" for Ceanothus came about due to the plants similar purple flower color and terminally-borne inflorescences.
Several species are reported to have medicinal properties by both native Americans and modern homeopathic practitioners, though the author was not able to locate peer-reviewed publications supporting the efficacy of these species.
IN BLOOM CONTRIBUTORS: Text by Corey Barnes. Profile by Mona Bourell. Photos by Joanne Taylor, Mona Bourell, and David Kruse-Pickler.