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Woollyleaf Ceanothus
Ceanothus tomentosus
About Woollyleaf Ceanothus (Ceanothus tomentosus) Nurseries Show All Photos Ceanothus tomentosus is a species of shrub in the Buckthorn family (Rhamnaceae) known by the common name Woollyleaf Ceanothus. It is most commonly found in the foothills and canyons of San Diego, Orange and Riverside Counties, north up into the foothills of the Transverse Mountains, and south down into Baja California. There is a separate population in the foothills of the central Sierra Nevada. Ceanothus tomentosus grows in chaparral, coastal sage scrub, coastal strand and foothill woodland plant communities in its range.

It is an erect shrub approaching four meters in maximum height. The woody parts are reddish, especially when new. The evergreen leaves are alternately arranged, oval in shape, dark green and slightly hairy on top and woolly on the undersides. They are edged with tiny hairy teeth. The flower cluster is several centimeters long of deep blue to light blue flowers. Rarely white. The fruit is a lobed capsule a few millimeters long which is sticky when new.

Ceanothus tomentosus is a quintessential chaparral plant in San Diego county. It puts on a great floral display for 1-2 months in winter or occasionally in the spring if rains come late. The flowers are beautiful and abundant particularly in wetter years, and can turn the foothills and canyons blue. So for 1-2 months this is a truly spectacular plant. The rest of the year it's still a nice plant, with small shiny rounded leaves, toothed in the summer with tiny reddish brown thorns on the sides. The shiny leaves reflect the sun and look beautiful backlit. In southern California, it prefers full sun and slopes that retain just a bit more moisture than average - i.e. north facing slopes, slope bottoms, east or west facing slopes with heavier soils and plenty of rocks, or cool coastal conditions. Fast growing to 6-12 feet if happy.

Ceanothus tomentosus doesn't tolerate much if any direct summer water after it's established, and if planted in soils that don't retain enough moisture, it will dry out and die. So site selection is very important here. Best to give it regular water for the first year, and none or almost none thereafter, though it'll do fine if planted adjacent to an irrigated area. If you do give it supplemental water, it should be light and preferably indirect. It will typically drop about half its leaves in the summer and make its own mulch.
Plant Description
Plant Type

Max. Height
6 - 13.1 ft (1.8 - 4 m)

Max. Width
6 - 12 ft (1.8 - 3.7 m)

Rounded, Upright Columnar


Growth Rate


Small, oval or nearly round, dark green, toothed with black spikes in the summer,

Flower Color
Blue, Lavender, White

Flowering Season
Spring, Winter

Native Status

Natural Setting
Site Type
Dry rocky slopes, usually north facing, sandstone bluffs near the coast, from near sea level to 6,800 ft.

Part Shade, Sun

Elevation ?
11' - 7419'

Annual Precip. ?
10.2" - 70.5"

Summer Precip. ?
0.22" - 2.45"

Coldest Month ?
30.6° F - 56.0° F

Hottest Month ?
53.4° F - 80.2° F

Humidity ?
0.98 vpd - 28.75 vpd

Soil Description
Prefers heavier or rockier soils on slopes, lighter soils on flats

Soil PH
5 - 8

Fast, Medium

Cold Tolerance(° F)
Tolerates cold to 10 - 15° F

Sunset Zones ?
7, 14, 15*, 16*, 17, 18, 19, 20*, 21*, 22*, 23*, 24*

Companion Plants
Ceanothus crassifolius, Spiny redberry, Mission Manzanita, Black Sage, White Sage, Scrub Oaks, Toyon, Bush Rue

Wildlife Attracted
Important wildlife plant. Attracts many butterfly species, many bee species and other pollinators, many bird species. Plants in the Ceanothus genus are host plants to the Spring Azure, Echo Blue, Pacuvius Duskywing, California Tortoiseshell, Pale Swallowtail, and Hedgerow Hairstreak butterflies.

Landscaping Information
Ease of Care
Moderately Easy

Water Requirement ?
Very Low
Extremely Low
Very Low
Moderate - High

Seldom Used

Max. Summer Water ?
No Summer Water
Keep moist

Organic with Rocks

Propagation ?
For propagating by seed: Hot water treatment.  For propagating by seed: Hot water treatment.

Common uses
Hedges, Bank Stabilization, Deer Resistant, Bird Gardens, Butterfly Gardens, Bee Gardens

Nursery Availability
Sometimes Available

Other Names
Botanical Names
Ceanothus tomentosus var. olivaceus,Ceanothus tomentosus var. tomentosus

Common Names
Woolly-leaf Ceanothus, Woolyleaf Ceanothus

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

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