Ceanothus

Ceanothus
File:Ceanothus americanus.jpg
Ceanothus americanus flowers
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Rosales
Family:	Rhamnaceae
Genus:	Ceanothus L.
Species
See text

Ceanothus L. /ˌsiːəˈnoʊθəs/ is a genus of about 50–60 species of nitrogen-fixing shrubs or small trees in the family Rhamnaceae. Common names for members of this genus are California lilac, wild lilac, and soap bush. "Ceonothus" comes from a Greek word meaning "spiny plant", κεανοθος (keanothos), which was applied by Theophrastus (371-287 BC) to an Old World plant believed to be Cirsium arvense.

The genus is confined to North America, with the center of its distribution in California. Some species (e.g. C. americanus) are found in the eastern United States and southeast Canada, and others (e.g. C. coeruleus) extend as far south as Guatemala. Most are shrubs 0.5–3 m tall, but C. arboreus and C. thyrsiflorus, both from California, can be small trees up to 6–7 m tall.

Description

File:Ceanothus arboreus 2.jpg

Ceanothus arboreus illustrating the three parallel leaf veins characteristic of plants in this genus

Growth pattern

The majority of the species are evergreen, but the handful of species adapted to cold winters are deciduous. The leaves are opposite or alternate (depending on species), small (typically 1–5 cm long), simple, and mostly with serrated margins.

Leaves and stems

Ceanothus leaves may be arranged opposite to each other on the stem, or alternate. Alternate leaves may have either one or three main veins rising from the base of the leaf.

The leaves have a shiny upper surface that feels "gummy" when pinched between the thumb and forefinger, and the roots of most species have red inner root bark.

Flowers and fruit

File:Ceanothus fendleri flower1.jpg

Flower of Ceanothus fendleri

The flowers are white, greenish–white, blue, dark purple-blue, pale purple or pink, maturing into a dry, three-lobed seed capsule.

The flowers are tiny and produced in large, dense clusters. A few species are reported to be intensely fragrant almost to the point of being nauseating, and are said to resemble the odor of "boiling honey in an enclosed area." The seeds of this plant can lie dormant for hundreds of years, and Ceanothus species are typically dependent on forest fires to trigger germination of their seeds.

Fruits are a hard, nut-like capsule.

Ecology

Ceanothus is a good source of nutrition for deer, specifically mule deer on the west coast of the USA. However, the leaves are not as nutritious from late spring to early fall as they are in early spring. Porcupines and quail have also been seen eating stems and seeds of these shrubs. The leaves are a good source of protein and the stems and leaves have been found to contain a high amount of calcium.

Distribution

File:Ceanothus.jpg

Ceanothus americanus (fruit left, flowers right)

Plants in this genus are widely distributed and can be found on dry, sunny hillsides from coastal scrub lands to open forest clearings up to 9,000 feet. These plants are profusely distributed throughout the Rocky Mountains from British Columbia south through Colorado, the Cascades of Oregon and California, and the Coastal Ranges of California.

Ceanothus velutinus is the most common member of this genus and is widespread throughout North America.

Cultivation

File:Ceanothus cuneatus1.jpg

Flowers of Ceanothus cuneatus, at Pinnacles National Park, California

Many species are popular garden ornamental plants, and dozens of hybrids and cultivars have been selected, such as 'Flexible ceanothus', Ceanothus × flexilis Greene ex McMinn (C. cuneatus × C. prostratus).

The following cultivars and hybrids have gained the Royal Horticultural Society's Award of Garden Merit:-

'Blue mound' 'Burkwoodii' 'Cascade'

'Concha' 'Dark Star'

'Puget Blue' 'Gloire de Versailles' 'Topaze'

(See also C. arboreus and C. thyrsiflorus).

Propagation

File:Ceanothus integerrimus 01.jpg

California Lilac (Ceanothus integerrimus) in Yosemite, 2005

Propagation of ceanothus is by seed, following scarification and stratification. Seeds are soaked in water for 12 hours followed by chilling at 1 °C for one to three months. It can also sprout from roots and/or stems. Seeds are stored in plant litter in large quantities. It is estimated that there are about two million seeds per acre in forest habitats. Seeds are dispersed propulsively from capsules and, it has been estimated, can remain viable for hundreds of years. In habitat, the seeds of plants in this genus germinate only in response to range fires and forest fires.

Other uses

Native Americans used the dried leaves of this plant as an herbal tea, and early pioneers used the plant as a substitute for black tea. Miwok Indians of California made baskets from ceanothus branches. C. integerrimus has been used by North American tribes to ease childbirth.

Names

The Californian species are sometimes known as California lilac, but species found elsewhere have other common names, such as New Jersey tea for C. americanus (as its leaves were used as a black tea substitute during colonial times). In garden use, most are simply called by their scientific names or an adaptation of the scientific name, such as 'Maritime ceanothus' for C. maritimus.

Selected species

Ceanothus americanus L. – New Jersey Tea; Red Root Ceanothus arboreus Greene – Feltleaf Ceanothus Ceanothus confusus J.T. Howell – Rincon Ridge Ceanothus Ceanothus connivens Greene – Trailing Buckbrush Ceanothus cordulatus Kellogg – Whitethorn Ceanothus Ceanothus crassifolius Torr. – Hoaryleaf Ceanothus Ceanothus cuneatus (Hook.) Nutt. – Buckbrush Ceanothus cuneatus var. fascicularis (McMinn) – Hoover Sedgeleaf Buckbrush Ceanothus cuneatus var. rigidus (Nutt.) Hoover – Monterey Ceanothus Ceanothus cyaneus Eastw. – San Diego Buckbrush Ceanothus dentatus Torr. & A.Gray – Sandscrub Ceanothus Ceanothus depressus Benth. – junco Ceanothus divergens Parry – Calistoga Ceanothus Ceanothus diversifolius Kellogg – Pinemat Ceanothus fendleri A.Gray – Fendler's Ceanothus Ceanothus ferrisiae McMinn – Coyote Ceanothus Ceanothus foliosus Parry – Wavyleaf Ceanothus Ceanothus foliosus var. foliosus – Wavyleaf Ceanothus Ceanothus foliosus var. medius McMinn – Wavyleaf Ceanothus Ceanothus foliosus var. vineatus McMinn – Vine Hill Ceanothus Ceanothus fresnensis Dudley ex Abrams – Fresno Ceanothus Ceanothus gloriosus J.T. Howell – Point Reyes Ceanothus Ceanothus gloriosus var. exaltatus J.T. Howell – Point Reyes Ceanothus Ceanothus gloriosus var. gloriosus – Point Reyes Ceanothus Ceanothus gloriosus var. porrectus J.T.Howell – Mt. Vision Ceanothus Ceanothus greggii A.Gray – Desert Ceanothus Ceanothus greggii var. greggii – Desert Ceanothus Ceanothus greggii var. perplexans (Trel.) Jepson – Desert Ceanothus Ceanothus greggii var. vestitus (Greene) McMinn – Mojave Ceanothus Ceanothus griseus (Trel. ex B.L.Rob.) McMinn – Carmel Ceanothus Ceanothus hearstiorum Hoover & J.B.Roof – Hearst Ranch Buckbrush Ceanothus herbaceus Raf. – Jersey Tea Ceanothus impressus Trel. – Santa Barbara Ceanothus Ceanothus impressus var. impressus – Santa Barbara Ceanothus Ceanothus impressus var. nipomensis McMinn – Santa Barbara Ceanothus Ceanothus incanus Torr. & A.Gray – Coast Whitethorn Ceanothus integerrimus Hook. & Arn. – Deerbrush Ceanothus

Ceanothus jepsonii Greene – Jepson Ceanothus Ceanothus jepsonii var. albiflorus J.T.Howell – Jepson Ceanothus Ceanothus jepsonii var. jepsonii – Jepson Ceanothus Ceanothus lemmonii Parry – Lemmon's Ceanothus Ceanothus leucodermis Greene – Chaparral Whitethorn Ceanothus maritimus Hoover – Maritime Ceanothus Ceanothus martinii M.E.Jones – Martin's Ceanothus Ceanothus masonii McMinn – Mason's Ceanothus Ceanothus megacarpus Nutt. – Bigpod Ceanothus Ceanothus megacarpus var. insularis (Eastw.) Munz – Island Ceanothus Ceanothus megacarpus var. megacarpus – Bigpod Ceanothus Ceanothus microphyllus Michx. – Littleleaf Buckbrush Ceanothus oliganthus Nutt. – Hairy Ceanothus Ceanothus ophiochilus Boyd, Ross & Arnseth – Vail Lake Ceanothus Ceanothus otayensis H. E. McMinn – Otay Mountain Buckbrush Ceanothus palmeri Trel. – Palmer Ceanothus Ceanothus papillosus Torr. & A.Gray – Wartleaf Ceanothus Ceanothus papillosus var. papillosus – Wartleaf Ceanothus Ceanothus papillosus var. roweanus McMinn – Wartleaf Ceanothus Ceanothus parryi Trel. – Parry Ceanothus Ceanothus parvifolius (S.Watson) Trel. – Littleleaf Ceanothus Ceanothus pinetorum Coville – Coville Ceanothus Ceanothus prostratus Benth. – Prostrate Ceanothus Ceanothus pumilus Greene – Dwarf Ceanothus Ceanothus purpureus Jepson – Hollyleaf Ceanothus Ceanothus roderickii Knight – Pine Hill Buckbrush Ceanothus sanguineus Pursh – Redstem Ceanothus Ceanothus serpyllifolius Nutt. – Coastal Plain Buckbrush Ceanothus sonomensis J.T. Howell – Sonoma Ceanothus Ceanothus sorediatus Hook. & Arn. – Jimbrush Ceanothus Ceanothus spinosus Nutt. – Green Bark Ceanothus Ceanothus thyrsiflorus Eschsch. – Blueblossom Ceanothus tomentosus Parry – Woolyleaf Ceanothus Ceanothus velutinus Dougl. ex Hook. – Snowbrush Ceanothus Ceanothus velutinus var. hookeri M.C. Johnston – Hooker's Ceanothus Ceanothus velutinus var. velutinus – Snowbrush Ceanothus Ceanothus verrucosus Nutt. – Barranca Brush

Formerly placed here

• Adolphia infesta (Kunth) Meisn. (as C. infesta Kunth)
• Colubrina arborescens (Mill.) Sarg. (as C. arborescens Mill.)
• Colubrina asiatica (L.) Brongn. (as C. asiaticus L.)
• Colubrina elliptica (Sw.) Brizicky & W.L.Stern (as C. reclinata L’Hér.)
• Noltea africana (L.) Endl. (as C. africanus L.)

See also

• California chaparral and woodlands

References

1. University of Wisconsin–Stevens Point Plant Database: Ceanothus americanus
2. Moerman, D. (1988). Native American Ethnobotany. Timber Press, Oregon.