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Plant of the Month   ~~   MARCH 2006

updated on or about the 1st of each month

Image of Ceanothus


  • Common Name(s): Ceanothus, California Lilac, Wild Lilac, Soap Bush, Mountain Lilac, Blue Blossom
  • Scientific Name: Ceanothus species
  • Family: Rhamnaceae, Buckthorn family
  • Plant Type: evergreen or deciduous shrub, or small tree
  • Size: 5 to 20 feet high
  • Common Habitat: Chaparral, ridges, slopes, woodland, coastal scrub

There are six species of Ceanothus that can be found in the Santa Monica mountains, and about ten times that number of varieties are able to be grown in California. Our natives bloom from January to May. Flower colors range from white to various shades of blue, and are found in clusters. Subtle yet conspicuous, whole hillsides lighten up in the spring when these plants are in bloom.

Characteristically, Ceanothus need good drainage, tolerate cold, heat, and wind, are adapted to fire, and are generally low maintenance. If you have ever done trail maintenance that involved cutting this plant, you may remember the sharp spines on its branches; Ceanothus means spiny plant in Greek. The common name of "Soap Bush" is earned because the flowers of some varieties will develop a lather when rubbed with water.

The following chart gives some distinguishing characteristics of the six kinds native to our mountains.

Common name Species Flowers Bloom Time Other characteristics
Big-Pod Ceanothus Ceanothus megacarpus white Jan-Apr very common especially on southern or coastal slopes; gray-brown bark with fluted trunk; oval leaves; fruit is horned; in mid-summer seedpods explode, ejecting seedpods that are its means of reproducing after a fire
Greenbark Ceanothus, Redheart Ceanothus Ceanothus spinosis light blue to white Feb-May Smooth green bark; especially spiny; open-branched or tree-like form; smooth, shiny leaves; fruit is not horned
Hairy-Leaf Ceanothus Ceanothus oliganthus deeper blue Feb-Apr prefers higher, shadier or coastal locations; reddish-tinted branches with tree-like trunk; leaves larger than other varieties, oval, jagged with terminal points; fruit is not horned
Hoary-Leaved Ceanothus Ceanothus crassifolius white Jan-Apr tough plant tolerant of extreme temperatures and drought; open-branched; small, thick, toothed leaves; fruit is horned
Buckbrush Ceanothus cuneatus white Feb-May prefers inland over the coast; erect shrub; wedge-shaped leaves; fruit is horned
White Thorn Ceanothus leucodermis white to blue Apr-Jun not very common; pale green smooth bark; white powdery coating on top of shiny, oval-pointed leaves; fruit is not horned

Image of Ceanothus Image of Ceanothus

Contributed by Liz Baumann

Curious what was featured in past Plants of the Month? Search the Archives.

Wildflowers of the Santa Monica Mountains, by Milt McAuley
Flowering Plants: The Santa Monica Mountains, Coastal and Chaparral Regions of Southern California, by Nancy Dale
Roadside Plants of Southern California, by Thomas J. Belzer
California Native Plants for the Garden, by Carol Bornstein, David Fross, and Bart O'Brien
California Herbal Remedies, by LoLo Westrich

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