Palmer Lilac (Ceanothus palmeri) is a native shrub that grows in California, primarily in the Sierra Nevada Foothills and Peninsular Range regions. It tends to grow in dry slopes, at elevations from 3000-6000 feet. Form is mostly upright though sometimes more rounded. Flowers are usually white but can be light blue to lavender.

Ceanothus papillosus, Wartleaf ceanothus, is a species of plant in the genus Ceanothus. It is endemic to California, where it grows in open habitat on the slopes of the coastal mountain ranges, such as woodland and chaparral. The evergreen leaves are alternately arranged, often in crowded clusters, each oblong to long-rectangular in shape and covered in glandular bumps. The edges are generally turned under and lined with glandular hairs. The inflorescence is a cluster of bright blue flowers. The fruit is a bumpy capsule about 3 millimeters long. The evergreen leaves are alternately arranged, often in crowded clusters, each oblong to long-rectangular in shape and covered in glandular bumps. The edges are generally turned under and lined with glandular hairs. The inflorescence is a cluster of bright blue flowers. The fruit is a bumpy capsule about 3 millimeters long.

Tolerates almost any soil type. Prefers sun in coastal sites, and part shade in inland sites. Selected by Dara Emery in 1981 from Wheeler Gorge in Ventura County. Introduced by santa Barbara Botanic Garden.

Ceanothus parryi is a species of shrub in the buckthorn family Rhamnaceae known by the common name Parry ceanothus. It is native to Oregon and northern California, where it grows in the canyons of coastal mountain ranges. It is an erect shrub approaching 5 meters in maximum height. The woody parts are reddish brown and woolly when new, darkening with age and shedding most of the hairs. The evergreen leaves are alternately arranged, oval in shape and edged with hairy teeth. They are dark green and hairless on the upper surfaces, paler and woolly on the undersides. The flower cluster is a long cluster of deep blue flowers, up to about 15 centimeters long. The fruit is a smooth, 3-lobed capsule a few millimeters long.

Ceanothus parvifolius is a species of shrub in the buckthorn family Rhamnaceae known by the common name littleleaf ceanothus. It is endemic to the High Sierra Nevada of California, where it grows in moist areas in the forest. This is a spreading shrub, growing to a maximum height of just over a meter, forming a wide bush. The woody parts are reddish in color and hairless. The leaves are alternately arranged and deciduous. They are less than 2 centimeters long, mainly oval in shape and smooth-edged, sometimes with a few tiny teeth near the tip. The plentiful flower clusters are clusters several centimeters long of flowers in shades of very pale to deep blue. The fruit is a 3-lobed smooth capsule a few millimeters long.

Ceanothus pinetorum is a species of shrub in the buckthorn family Rhamnaceae known by the common names Kern ceanothus and Coville ceanothus. It is endemic to the Sierra Nevada of California, where it is known only from the Kern Plateau, a section of the southern Sierra featuring wide meadows and ridges. This is a low-lying shrub forming a bush or mat under a meter tall but up to about 8 meters in spreading width. The evergreen leaves are oppositely arranged and generally under 2 centimeters long, each firm and hairless with a toothed edge. The inflorescence is a small cluster of blue to off-white flowers yielding horned, wrinkled fruits just under a centimeter long. This is a low-lying shrub forming a bush or mat under a meter tall but up to about 8 meters in spreading width. The evergreen leaves are oppositely arranged and generally under 2 centimeters long, each firm and hairless with a toothed edge. The inflorescence is a small cluster of blue to off-white flowers yielding horned, wrinkled fruits just under a centimeter long.

Ceanothus prostratus is a species of shrub in the Buckthorn family (Rhamnaceae) known by the common names prostrate ceanothus and mahala mat. It is native to the Pacific Northwest of the United States, into northern California and Nevada, where it grows in coniferous forest and open plateau. This is a flat, mat-forming shrub growing 6 inches tall up to about 8 ft. wide. The evergreen leaves are oppositely arranged, oval in shape with several large, sharp teeth along the edges. The upper surface is green and hairless, and the underside is paler in color and feltlike in texture. The flower cluster is a small cluster of deep blue or purple flowers. The fruit is a wrinkled capsule one half to one centimeter long.

Ceanothus prostratus grows in the understory of mixed conifer forests, from foothills to subalpine areas. It also inhabits open flats and ridges in areas of low chaparral as well as dry interior forest ecosystems. It can be found from elevations ranging between 1,000 and 9,000 ft. It is notoriously difficult to grow due to unknown factors.

Large Leaved Mahala Mat (Ceanothus prostratus var. laxus) is a native shrub that grows in central and northern California.

Ceanothus pumilus is a species of shrub in the buckthorn family Rhamnaceae known by the common names dwarf ceanothus and Siskiyou mat. It is native to the mountains of southern Oregon and northern California, where it grows in habitat such as coniferous forest and chaparral, often on serpentine soils. This is a low-lying to flat shrub taking the form of a mat or bramble up to about 2.5 meters wide. The tiny evergreen leaves are oppositely arranged, each just over a centimeter in maximum length. They are firm and ribbed, flat or cupped, hairless on top and generally hairy and paler in color on the undersides. The flower cluster is a small cluster of flowers in shades of blue, lavender, or white. The fruit is a horned capsule about half a centimeter long.

Ceanothus purpureus, with the common name Hollyleaf ceanothus, is a species of shrub in the buckthorn family Rhamnaceae. It is endemic to northern California, where it is known only from the Inner North Coast Ranges north of the Bay Area, mainly in Sonoma and Napa Counties. The largest remaining population of this shrub occurs on Mt. George near Napa, where it is protected in a botanical preserve. The Ceanothus purpureus plant grows in woodland and chaparral habitat. It is spreading or erect in form, approaching 2 meters in maximum height. The woody parts are gray to reddish brown in color. The evergreen leaves are oppositely arranged and up to about 2. 5 centimeters long. They are round to oval, wavy, and edged with spiny teeth, resembling the leaf of holly. The inflorescence is a small cluster of blue or purple flowers. The fruit is a horned capsule about half a centimeter long.

Monterey Ceanothus (Ceanothus rigidus previously called Ceanothus cuneatus var. rigidus) is a rare native shrub that grows in Northern, Southern and Central California, primarily in the Central Coast and SF Bay regions. It tends to grow in dry fans, slopes and ridges, at elevations from 0-5900 feet.

Ceanothus rigidus is primarily available in nurseries as cultivars - the two most common of which are Ceanothus rigidus 'Snowball', and Ceanothus rigidus'' 'Sierra Snow'. Both have profuse white flowers, and a dense form with arching branches the former of The Snowball variety ranges from 4-5 high and 8 feet wide, and Sierra Snow ranges from 5-6 feet high and 10-15 feet wide. Both are relatively easy to grow in the natural coastal range of the straight Ceanothus rigidus species.

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and sun or part shade in inland sites. Selected by Nevin smith, suncrest Nursery.

Ceanothus 'Snowball' is a dense, mounding shrub that is covered in pure white balls of flower clusters in the spring. The flowers really stand out against the plant's arching branches of dark green, leathery leaves. Snowball grows 4' tall and can spread to 10'. It is best near the coast but can take inland heat and drought, as well as heavier soils, as long as it gets some afternoon shade and a bit of summer water. It likes to keep it's roots cool but dry in the summer and will respond well to a quick rinsing off of it leaves every week or so in the summer. Just make sure you don't get the soil wet! Try it on a hillside or let it cascade over a wall. Horticultural selection by Lester Rowntree, C. cuneatus var. rigidus: origin = cuttings (1950) Yankee Pt., central coast, Monterey Co.; intro Rancho Santa Ana Botanic Garden 1954.

Ceanothus roderickii is a rare species of shrub in the buckthorn family Rhamnaceae known by the common name Pine Hill ceanothus. It is endemic to western El Dorado County, California, where it grows in the chaparral and woodlands of the Sierra Nevada foothills, such as the Pine Hill Ecological Reserve. It is named after 20th century California flora explorer, botanist, and arboretum director Wayne Roderick. This rare shrub is up to about 3 meters wide and flat, forming low brambles or mats. The grayish brown stems root at nodes as they grow horizontally along the ground. The tiny evergreen leaves are oppositely arranged. Each is only about a centimeter long, widely lance-shaped and smooth along the edges or sometimes toothed near the tip. The top surface is green and hairless and the underside is somewhat woolly. The inflorescence is a small cluster of white to pale blue flowers. The fruit is a capsule about half a centimeter long, sometimes bearing small horns on top. Habitat. Ceanothus roderickii is found almost exclusively on soils of gabbro origin in the Pine Hill Geological Formation. It is a federally listed endangered species. This endangered plant was first collected in 1956 near Shingle Springs. It is threatened by several factors, including suppression of the wildfire it requires for reproduction, off-road vehicles, road maintenance and construction, and development. There are ten to twenty remaining occurrences.

Ceanothus sanguineus is a species of shrub in the buckthorn family Rhamnaceae known by the common name redstem ceanothus. It is native to western North America from British Columbia to Montana to far northern California; it is also known from Michigan. It grows in temperate coniferous forest habitat in forest openings amidst the conifers. This is an erect shrub approaching 3 meters in maximum height. Its stem is red to purple in color, its woody parts green and hairless when new. The deciduous leaves are alternately arranged and up to about 10 centimeters long. They are thin, light green, oval, and generally edged with hairy teeth. The undersides are sometimes hairy. The flower cluster is a cluster of white flowers up to about 12 centimeters long. The fruit is a three-lobed smooth capsule about 4 millimeters long. This shrub is an important food plant for wild ungulates such as the Rocky Mountain Elk, it is browsed eagerly by many types of livestock, and the seed is consumed by many types of animals. Like many other Ceanothus, this species requires wildfire for reproduction and proliferation; its seeds are activated by heat and the plant is intolerant of the shade produced by an overgrown forest.

Ceanothus sonomensis, with the common name Sonoma ceanothus, is a rare species of shrub in the buckthorn family Rhamnaceae. It is endemic to northern California. Ceanothus sonomensis is known only from the Hood Mountain Range. Most of its 10 or so occurrences are located in Sonoma County, and one remains in Napa County. Ceanothus sonomensis is a member of the chaparral plant community in the California montane chaparral and woodlands sub-ecoregion.

Ceanothus spinosus is a species in the Rhamnaceae (Buckthorn) family known by the common names greenbark ceanothus and redheart. It is native to the coastal strip of southern California south of San Luis Obispo County to northern Baja California, where it grows in the scrub and chaparral of the coastal mountain ranges. This is a large treelike shrub approaching six meters in maximum height. The stem is a rough-barked trunk near the base and has thorny, greenish-brown branches. The thick, firm evergreen leaves are up to 4 or 5 centimeters long and are hairless on the upper surface but sometimes lined with hairs underneath. The shrub blooms in flower clusters up to 15 centimeters long filled with clusters of white to pale blue flowers. The fruit is a smooth, round capsule about half a centimeter wide containing 3 seeds.

Blueblossom ceanothus (Ceanothus thyrsiflorus) is a large shrub or small tree in the Buckthorn family (Rhamnaceae). Evergreen, glossy leaves range from bright green to dark green. Small flower clusters range in color from light blue, dark blue, or blue-violet; occasionally a specimen with pale blue-white flowers can be found. Varying dramatically in form and size over its natural range, some plants grow fairly upright to 30 feet and others grow in a mounding form to only 2-3 feet tall. Flowers appear in late winter or early spring, and are an important early source of food for pollinators. Bees are especially attracted to the flowers. Three-lobed seed capsules are eaten by birds and small mammals. 

Blueblossom grows primarily along the coast and coastal mountains, in many different habitats, in full sun or part shade. In the hotter, inland part of its range, it can be found growing in the shade of northern slopes, under mature woodland canopies, or closer to an irrigated or a naturally moist area. In the cooler, coastal areas, it prefers more sun and dry locations.

In the garden, if you continue to provide summer irrigation after it is established, ceanothus species will usually be short-lived. Choose a ceanothus which is native to your location, then stop irrigating after year two or three. Blueblossom can be used alone as a backdrop to shorter shrubs and perennials, or as an evergreen hedge. Prune it to one trunk for a treeform, or keep it natural for a large shrub. When in bloom, blueblossom is almost entirely covered in flowers, creating a dreamy blue haze in the landscape. There are many cultivars available at nurseries all over the state. 

Horticultural selection from Ceanothus thyrsiflorus. This garden selection grows to 4 feet high x 6-1 wide. Bright shiny evergreen leaves and medium-blue flowers in spring. It makes a large mounding shrub or ground cover, great for erosion control massed on slopes and banks, or a low, informal hedge. Plant in full sun in coastal gardens, provide partial shade inland. Attracts bees and butterflies. Hardy to 15 degrees F.

Horticultural selection C. thyrsiflorus: origin = cuttings (198) Arroyo de la Cruz, san Luis Obisbo Co.; intro Nevin smith, suncrest Nurseries 1981 Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and sun or part shade in inland sites. Collected by Nevin smith in 1981 from Arroyo de la Cruz in san Luis Obispo Co; introduced by Wintergreen Nursery.

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. A patented selection discovered in 1996 at Yoder Toddington of Littlehampton, England. Variegated selection off of C. thyr. v. thyr. 'Zanzibar'.

Horticultural selection from Ceanothus thyrsiflorus from Big sur in the central California coast. This large lilac has brilliant clusters of white flowers that appear profusely in spring. It is fast growing, with long arching branches.Although it is a selection from the central coast we have been observing its performance in an Escondido garden with a harsh inland climate and it has done extremely well. This lilac will tolerate heavy soil and some summer water. We recommend part shade in inland areas. This lilac is well suited as a pretty, natural screen. It will tolerate some pruning. You will enjoy the flowers in spring and songbirds will find it to be an attractive home!

'Snow flurry' is a horticultural selection from Big sur, central coast, Monterey Co.and was introduced by Joe solomone 1975. Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. Collected by Joseph solomone in 1975 on Big sur Coast.

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. Introduced by the saratoga Horticultural Research Foundation in 1981; Award of Garden Merit by the Royal Horticultural society in 1984.

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. Selected for the garden.

Carmel ceanothus (Ceanothus thyrsiflorus var. griseu) is a flowering shrub available in many named cultivars. In winter to spring its evergreen leaves are densely covered with small blue or purple flowers. This native plant is endemic to coastal California. It grows in the chaparral, coastal scrub, and closed-cone-pine forest plant communities.

The flowers become food sources for larvae of some butterfly and moth species, bees, and other beneficial insects. 

Carmel ceanothus is the most popular ceanothus for California garden. Gardeners find it easy to grow and fast-growing. It will take a wide range of soils and can tolerate summer water up to twice a week.

Take care with pruning and do not prune heavily. You should not cut back into old wood. Instead, promote new shoots by pruning the tip of stems where growth is active. Also, you can trim off dead branches on the interior of the shrub to improve its shape and attractiveness. 

Cultivars of Carmel ceanothus have variable leaf and flower colors and grow to different heights and widths.  Calscape features:

Diamond heights mountain lilac (Ceanothus thyrsiflorus var. griseus 'Diamond Heights') 

Kurt Zadnik Carmel ceanothus (Ceanothus thyrsiflorus var. griseus 'Kurt Zadnik') 

Louis Edmunds Carmel ceanothus (Ceanothus thyrsiflorus var. griseus 'Louis Edmunds') 

Point Sal Carmel creeper (Ceanothus thyrsiflorus var. griseus 'Point Sal') 

Santa Ana Carmel ceanothus (Ceanothus thyrsiflorus var. griseus 'Santa Ana') 

Yankee Point Carmel Ceanothus (Ceanothus thyrsiflorus var. griseus 'Yankee Point') 

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. Garden selection. This species previously known as Ceanothus griseus var. horizontalis.

Horticultural selection from Ceanothus thyrsiflorus var. griseus. In the mainstream horticultural trade continues to use the older name for, which is Ceanothus griseus var. horizontalis This unusual low growing Ceanothus hybrid will definitely appeal to those who are attracted to variegated foliage. A bright low-growing shrub with chartreuse leaves splashed with dark green. Foliage is brightest in warm weather and full sun, and will be greener in winter or if heavily shaded. Remove any stems with solid green leaves that periodically develop.This ceanothus is fast growing to 1' tall and 4' to 6' wide, with light blue flowers appearing in spring. We recommend placing in full sun on the coast and shade or part shade inland. It is an excellent choice for containers, along a shady border or spilling over a wall. Diamond Heights Ceanothus is suitable for planting in the dry shade beneath native oaks and combines well with Blue-eyed grass and Coffeeberry. Frost hardy to 2 degrees F, and drought tolerant once established.

This was a sport selected by Barry Lehrman in 1985 from a planting of Carmel Creeper (Ceanothus griseus var. horizontalis), that was found in the Diamond Heights neighborhood on Mount Davidson, in the center of san Francisco Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. Selected by Barry Lehrman in 1985 from the Mount Davidson area of san Francisco and named for the housing development where it was found.

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and sun or part shade in inland sites. Selected by Roger Raiche in 1986 from sonoma Co. coast; introduced in 1991.

Louis Edmunds Carmel Ceanothus is a mounding shrub ground cover, reaching 3-6 ft. tall by 12-25 ft. wide. It has dark green glossy textured foliage, and produces violet-blue flowers in the springtime. The plant can grow in full sun in coastal sites, and in some sun to part shade in inland sites. In cultivation it is tolerant of clay, alkalinity, sand, wind and heat, and depending on local climate and soil can be tolerant of some irrigation.
Ceanothus thyrsiflorus var. griseus 'Louis Edmunds' is planted as a large scale groundcover where it has room to spread, and for slope stabilization and erosion control.

This cultivar was selected in 1942 by nurseryman Louis L. Edmunds, who later operated the Louis Edmunds Native Plant Nursery in Danville, from a seedling he propagated and selected at Tilden Botanic Garden (Regional Parks Botanic Garden) in the Berkeley Hills. Ceanothus thyrsiflorus var. griseus 'Louis Edmunds' was given an Award of Merit in 1956 by the California Horticultural Society.

Tolerates almost any soil type. Prefers sun in coastal sites, and part shade in inland sites. Selected for the garden by Carol Bornstein.

Grows best in sandy, coarse-grained or other fast draining soil. Prefers sun in coastal sites, and part shade in inland sites. Selected by Louis Edmunds near point Arena in 1949.

Horticultural selection of cuttings of Ceanothus griseus horizontalis from Yankee Point on the central California coast just south of Carmel. This is one of the most commonly used California native plants. Yankee Point is a very garden tolerant spreading groundcover, with glossy green leaves and 1' blue flowers. On the coast, it will take wind and salt spray, and it will do equally well inland. It is often used as a large-scale groundcover and will stabilize slopes nicely. It reaches 2'-3' in height and spreads to 6'+. Horticultural selection E. griseus horizontalis: origin = cutting (1954) sHF, Yankee Pt., central coast, Monterey Co.; intro saratoga Hort. Foundation 1956 .Tolerates almost any soil type. Prefers sun in coastal sites, and sun or part shade in inland sites. Selection developed by Maunsell Van Rensselaer in 1954. Species previously known as C. griseus var. horizontalis.

Creeping Blueblossom (Ceanothus thyrsiflorus var. thyrsoflorus) is a the low growing form and variety of the native shrub and tree Ceanothus thyrsiflorus. It native range is coastal central and northern California, extending from northern Santa Barbara County to near the Oregon border, growing 1- 5 miles from the shore. The other variety of this species, Ceanothus thyrsiflorus var. griseus (Carmel Ceanothus) is much more variable in form and is native to habitats closer to the coast.
Creeping Blueblossom was previously classified as Ceanothus thyrsiflorus var. repens.

Creeping Blueblossom has profuse attractive sky blue flowers and makes an excellent ground cover plant. It prefers full sun to part shade in cooler coastal environments, and part shade to full shade in hotter and drier inland environments. It tolerates occasional light summer water, but is quite drought tolerant. It grows well in many different soil types, from clay to sand, and can tolerate poorly draining and fast draining conditions.

Cultivars in the nursery trade include:
Ceanothus thyrsiflorus var. thyrsiflorus 'Taylor's Blue' (Taylors Blue Ceanothus). This is a shrub ground cover growing 2-3 feet tall by 10-15 feet wide. It was introduced in the 1950s as Ceanothus thyrsiflorus 'Louis Edmunds' by the Saratoga Horticultural Foundation, from a plant in nurseryman Ken Taylor's natives garden in Aromas, originally from the garden of nurseryman Louis L. Edmunds. It was previously named and is sometimes still sold as C. t. var. repens 'Taylor's Blue'.
Ceanothus thyrsiflorus var. thyrsiflorus 'Louis Edmunds' (Louis Edmunds Blue Blossom). This is a prostrate ground cover growing 6 inches tall by 6 to 8 feet wide, and is the lowest cultivated form of C. t. var. thyrsiflorus. It introduced by Rancho Santa Ana Botanic Garden (California Botanic Garden) in 1958 as Ceanothus griseus 'Louis Edmunds' from a plant given them by Louis L. Edmunds, who operated the Louis Edmunds Native Plant Nursery in Danville.
This is not the same plant as the cultivar Ceanothus thyrsiflorus var. griseus 'Louis Edmunds' (Louis Edmunds Carmel Ceanothus) nor the formerly named Ceanothus thyrsiflorus 'Louis Edmunds' (currently C. t. var. thyrsiflorus 'Taylors Blue').

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. The plants formerly called Ceanothus tomentosus var. tomentosus from the Sierra Nevada are actually more closely related to Ceanothus thyrsiflorus (see Burge et. al. Nov. 2011). Ceanothus tomentosus grows in chaparral, coastal sage scrub, coastal strand and foothill woodland plant communities in its range.

It is shrub approaching four meters in maximum height. The evergreen leaves are alternately arranged and have dense, matted hairs on the undersides. The leaves have tiny, hairy teeth. The flower cluster is several centimeters long of deep blue or white flowers. The fruit is a lobed capsule a few millimeters long. It is not hairy and it 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 plant is especially spectacular. The shiny leaves reflect the sun and look beautiful when 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.

Ceanothus velutinus is a species of shrub in the buckthorn family, Rhamnaceae, known by the common names Red Root, Snowbrush Ceanothus and Tobacco Brush. It is native to western North America from British Columbia to California to Colorado, where it grows in several habitat types including coniferous forest, chaparral, and various types of woodland. In California it is found primarily in the northern half of the state in the Coast Ranges, Sierras, Klamath and Modoc regions. It can grow up to 4 meters tall but generally remains under three, and forms colonies of individuals which tangle together to form nearly impenetrable thickets. The aromatic evergreen leaves are alternately arranged, each up to 8 centimeters long. The leaves are oval in shape with minute hairy teeth along the edges, and shiny green and hairless on the top surface. The plentiful flower clusters are long clusters of white flowers. The fruit is a three-lobed capsule a few millimeters long which snaps open explosively to expel the three seeds onto the soil, where they may remain in a buried seed bank for well over 200 years before sprouting. The seed is coated in a very hard outer layer that must be scarified, generally by wildfire, before it can germinate. Like most other Ceanothus, this species fixes nitrogen via actinomycetes on its roots.

Ceanothus verrucosus is a rare species of shrub in the Buckthorn family (Rhamnaceae) known by the common names wart-stem ceanothus, barranca brush, and white coast ceanothus. It is endemic to Baja California and San Diego County, where it grows in coastal chaparral and scrub. Much of the coastal land that hosts this plant in the San Diego area has been claimed for development, but many populations still remain scattered around the region, such as one protected at Torrey Pines. This is an erect shrub approaching 3 meters in maximum height. The evergreen leaves, each up to about 1.5 centimeters long, are alternately arranged on bumpy stems. The flowers are held in a cluster up to around a foot. The flower is white except for its characteristic dark center. The fruit is a capsule about half a centimeter long.

Ceanothus verrucosus is one of the easier Ceanothus species to grow in southern California. It seems to tolerate summer water slightly better, and tolerates tough drought conditions much better than most other southern California Ceanothus species. But it does best with monthly summer water it's first year, and then left alone after that. It produces a spectacular display of white flowers in late winter, often early March. It tends to grow in an attractive fanned-out form, and its leaves stay green and healthy looking even through a long dry summer with no water.