Biological Sciences, Santa Barbara City College

Biology 100: Concepts of Biology

Frangula californica ssp. occidentali (Rhamnus californica var. occidentali)
Coffeeberry or California Buckthorn

Coffeeberry or California buckthorn has two scientific names Rhamnus californica var. occidentalis and Frangula californica ssp. occidentalis. These are synonyms This shrub is called coffeeberry because its berries (fruits) contain two nut-like seeds that look like coffee beans.  Coffeeberry is an attractive shrub and is used horticulturally in both traditional gardens and native plant landscaping.  It is drought tolerant. 

Coffeeberry is an evergreen shrub, between 2 – 5 meters in height. In windy or exposed areas it is a smaller shrub but in inland or in sheltered areas it can spread to 8 meters in height.  In California, you can find coffeeberry in most regions west of the Sierra Nevada.  It is also found in southwest Oregon and is naturalized on the island of Hawai’i.

Frangula californica.  Image copyright J.S. Peterson @ USDA-NRCS PLANTS Database

 Leaves are a dark dull green, long in shape, and curl under at the edges.  They are arranged alternately on the stem. In dry locations the leaves tend to be small and thick and in moister locations the leaves relatively large and thin.

Frangula californica (Eschsch.) A. Gray ssp. californica Coffeeberry or California Buckthorn copyright Gary A. Monroe @ USDA-NRCS PLANTS DatabaseThe five-petalled flowers are bisexual and bloom from April to June.  The flowers are green-white in color and are small and inconspicuous.  They are found in clusters of 5 – 60 flowers.  The fruit, a berry, turns from red to purple and then to black over the summer. 

In the fall, when the more palatable herbaceous plants are consumed, coffeeberry becomes an important browse for sheep, goats and deer.  In winter, it is an important browse for mule deer herds.  Coffeeberry is also more important as a browse immediately after a fire.  Plants on recently burned sites are higher in crude protein and crude fibers than those in unburned stands.  Coffeeberry fruits are very attractive to birds and generally very few survive to fall to the ground beneath the parent plant.  Seed dispersal is mainly by birds.

After a fire or other disturbance such as cutting that removes the above ground stems, etc., coffeeberry sprouts vigorously from buds on the root crown and rapidly regains its original size and biomass.

Kingdom Plantae – Plants
Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons
Subclass Rosidae –
Order Rhamnales –
Family Rhamnaceae – Buckthorn family
Genus Frangula P. Mill–  buckthorn, frangula
Species - Frangula californica (Eschsch.) Gray –  buckthorn, California buckthorn
Subspecies - Frangula californica ssp. occidentalis (T.J. Howell) Kartesz & Gandhi – California buckthorn

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