San Diego Ceanothus, Ceanothus cyaneus

About San Diego Ceanothus (Ceanothus cyaneus) 16 Nurseries Carry This Plant

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Ceanothus cyaneus is a rare species of flowering shrub known by the common names San Diego Ceanothus and Lakeside Ceanothus. This Ceanothus is found in the mountains of San Diego County, California, and its range probably extends just into Baja California. Most of the remaining natural specimens are in a small area in the hills around Lakeside and Ramona in San Diego County. This is a tall, erect shrub which may approach 5 meters in height. Its spreading branches are gray-green, with the younger twigs a light greenish-brown. The evergreen leaves may be serrated and toothed with hairy knobs, or they may be smooth along the edges. The underside is a lighter green than the upper surface. The flower cluster may exceed 15 centimeters in length, bearing many bunches of flowers along the length of a greenish stalk. The long flowers exhibit protruding yellow anthers. The capsule fruits are about 4 millimeters long.

Ceanothus cyaneus can be tricky to grow in landscaping applications. After the first year, direct summer water will usually kill it, but it will often also die if it can't get it's roots to moisture over the summer. It's best to plant on dry rocky slopes near a damper area, such as a seasonal creek, or near an irrigated area, or even 5-10 feet from a bubbler. It does best if surrounded by rocks or other plants that can shade its roots from the sun. If happy, it produces profuse displays of flower ranging from bright blue to powder blue to dark purple in color. It does best on north facing slopes, but can also handle east or west facing slopes if there is nearby water.

Plant Description

Plant Type

Shrub

Size

8 - 16.4 ft tall
12 ft wide

Form

Rounded

Growth Rate

Fast

Dormancy

Evergreen

Fragrance

Fragrant - Pleasant

Flower Color

Blue, Purple

Flowering Season

Winter, Spring

Wildlife Supported

Very popular with bees and butterflies. Plants in the Ceanothus genus are host plants to the Spring Azure, Echo Blue, Pacuvius Duskywing, California Tortoiseshell, Pale Swallowtail, and Hedgerow Hairstreak butterflies.
Bird gardens

Butterflies & moths hosted ( 64 likely * ) SHOW ALL

Gray Hairstreak Strymon melinusStrymon melinus

Pale Tiger Swallowtail Papilio eurymedonPapilio eurymedon

Lorquin's Admiral Limenitis lorquiniLimenitis lorquini

California Tortoiseshell Nymphalis californicaNymphalis californica

The Brown Elfin Callophrys augustinusCallophrys augustinus

Pacuvius Duskywing Erynnis pacuviusErynnis pacuvius

Hedgerow Hairstreak Satyrium saepiumSatyrium saepium

Landscaping Information

Sun

Full Sun, Part Shade

Moisture

Low

Summer Irrigation

Never irrigate once established

Nurseries

Carried by 16

Ease of Care

Moderately Easy

Cold Tolerance

Tolerates cold to 25° F

Soil Drainage

Fast

Soil Description

Tolerates clay soil but does best in well drained decomposed granite. Soil PH: 6.0 - 8.0

Common uses

Bank Stabilization, Bird Gardens, Butterfly Gardens, Bee Gardens

Companion Plants

Use with other chaparral plants of southern California such as Manzanitas (Arctostahpylos species), toyon (Heteromeles arbutifolia), Lemonadeberry (Rhus integrifolia), California Encelia (Encelia californica), Sagebrush (Artemisia californica), California Buckwheat (Eriogonum fasciculatum), Chamise (Adenostem fasciculatum), Bush Rue (Cneoridium dumosum), Tree Poppy (Dendromecon rigida), Thickleaf Yerba Santa (Eriodictyon crassifolium), Flannel Bush (Fremontodendron species), Mallow (Malacothamnus species), Scrub Oak (Quercus berberidifolia), Sages (Salvia species), Dudleya species, cactus species and annuals.

Maintenance

Pruning is recommended to control its tendency toward straggly growth. Prune to desired shape in dry season to prevent infection.

Propagation?

For propagating by seed: Hot water; then 3 mos. stratification may improve germination.

Natural Setting

Site Type

Dry rocky slopes, foothills and inland valleys among chaparral primarily in the Peninsular Range of San Diego County. At higher elevations, also found in conjunction with pine forest

Climate

Annual Precipitation: 10.8" - 35.2", Summer Precipitation: 0.31" - 1.82", Coldest Month: 43.4" - 54.6", Hottest Month: 67.1" - 78.5", Humidity: 1.04" - 26.88", Elevation: 339" - 4641"

Alternative Names

Common Names: Lakeside Ceanothus, San Diego Buckbrush

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Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links: Jepson eFlora Taxon Page CalPhotos Wikipedia Calflora

San Diego Ceanothus

Ceanothus cyaneus

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San Diego CeanothusCeanothus cyaneus

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San Diego Ceanothus

Ceanothus cyaneus