Frangula californica (previously classified as Rhamnus californica) is a species of flowering plant in the buckthorn family native to western North America.[3][4][5] It produces edible fruits and seeds.[6] It is commonly known as California coffeeberry and California buckthorn.
The plant occurs in oak woodland and chaparral habitats, numerous others in its range.[8] Individual plants can live an estimated 100 to 200 years.[9][10] An abundance or dominance of this plant usually shows an imbalence in soil quality, due to it commonly being found in rich fertile soils.[11]Frangula californica can be found in forests mixed with redwood, evergreen, and red fir. This plant is also a common shrub found in the environment in Siskiyou Mountains, southwestern Oregon, and northern California within the forests.[11]
Description
Frangula californica is a shrub 0.9–3.7 metres (3–12 ft) tall.[8] It is variable in form across subspecies. In favorable conditions the plant can develop into a small tree over 3.7 metres (12 ft) tall.[3] More commonly it is a shrub between 0.9–1.8 metres (3–6 ft) tall.[3]
The branches may have a reddish tinge and the new twigs are often red in color. The alternately arranged evergreen leaves are dark green above and paler on the undersides. The leaves have thin blades in moist habitat, and smaller, thicker blades in dry areas. The leaves are an ovate to elliptic shape with a normally waxy-white undercoating on the bottom. Top surface of the leaf is glabrous, or smooth without hair.[7]
Inflorescence and fruit
The 1/8" greenish-yellow flowers occur in leaf axil clusters, with 5 sepals and 5 shorter petals.[8] The flowers bloom in May and June only.[8] The fruit is a juicy drupe, which may be green, red, or black depending on ripening progress. It is just under a centimeter long and contains two seeds that resemble coffee beans. Seeds have poor resistance to fire and are short lived. The viability or lifespan of the seeds lasts to a maximum of 9 months. Seeds normally germinate in average temperature, not being too hot or cold and under favorable moisture conditions.[10] The fruits are approximately 0.25 inches or 7–9 mm in diameter which normally form within pairs or clusters.[12] Leaves can range from a greenish-evergreen to a whitish hue.[7] Berries fully ripen in early fall, but can be challenging to collect due to birds who use the fruit as a resource. Ripening process for berries occurs mainly from July to November while leaves are fully developed around May.[10]
Frangula californica subsp. californica in flowerRipening fruit
Frangula californica subsp. californica — California coffeeberry; widespread in western California. Fruit with two seeds; twigs red; leaves with conspicuous veins.[14][15]
Frangula californica subsp. occidentalis — Western California coffeeberry; on serpentine soils in northern California and southwestern Oregon, in the Klamath Mountains and North California Coast Ranges. Fruit with three seeds; twigs brown; leaves with inconspicuous veins.[18][19]
The plant reproduces sexually by seed and vegetatively by sprouting. After wildfire or cutting, the plant generally resprouts from its root crown. Reproduction via seed is most common in mature stands of the plant. It produces seeds by 2 or 3 years of age. Seeds are mature in the fall. Seed dispersal is often performed by birds, which are attracted to the fruit; some plants are so stripped of fruit by birds that hardly any seeds fall below the parent plant.[9]
This long-lived plant is persistent and becomes a dominant species in many habitat types, such as coastal woodlands. In the absence of wildfire, the shrub can grow large, with a wide spread that can shade out other flora.[11] When fire occurs, the plant can be very damaged but it readily resprouts from the surviving root crown, which is covered in buds for the purpose. It reaches its pre-burn size relatively quickly.[9]
Parts of the plant, including the foliage and fruit, are food for wild animals such as mule deer, black bears, woodrats and many resident and migrating birds, as well as livestock.[9] Many cattle, goats, and sheep consider the berry of this plant to be a palatable food source, but is only heavily utilized where the annual growth of this plant is abundant.[10]
Two insects induce galls on California coffeeberry: a moth, Sorhagenia nimbosa, induces swelling along the leaf midrib, and a midge of the genus Asphondylia induces flower-bud galls.[23] The flower is an attactor for native bees and supports pollenation in areas with a high quantity of coffeeberry.
It is also used for erosion control, and is usually deer resistant.[9][25] Erosion control usually occurs with this plant on dry steep hillsides where the roots keep in place and protect the surrounding land from weather erosin.[11] Due to this plant being unpaltable to deer, it is commonly used for ornamental purposes, including landscape decor.[28] This plant is also drought tolerant and not difficult to maintain, due to it being easy to prune and shape.[28] As a pollinator plant it is of special value to native butterflies and bees.[24][29] Regeneration normally occurs quickly after fire and show constant vegtative regeneration, except when in extreme or abnormal conditions.[28]
Cultivars
Cultivars of the species, for use as an ornamental plant, include:[30]
Frangula (Rhamnus) californica 'Eve Case' — Eve Case coffeeberry; smaller and more compact (3-6' H x 3-4' W), with denser foliage and larger berries than other species.[26][31] Introduced by the Saratoga Horticultural Foundation in 1975.[32]
Frangula (Rhamnus) californica 'Leatherleaf' — Leatherleaf coffeeberry; with black-green foliage.[33]
Frangula (Rhamnus) californica 'Mount San Bruno' — smaller leaves, more dense and compact, particularly tolerant of garden conditions.[26][34]
Frangula (Rhamnus) californica ‘Seaview’ — a ground cover variety.[26]
Frangula (Rhamnus) californica ssp. tomentella 'Hoary' — covered with leaves, velvety smooth, blooms from January through April.[35]
Frangula (Rhamnus) californica "Mound San Bruno"— compact vertically, but wide horizontally
Frangula (Rhamnus) californica "Little Sur"— small and compact both in height and width, produces dark green leaves
Closeup of flower.
Food and medicine
The berries are sometimes eaten, and the seeds inside have been used to make coffee substitute with limited success. The berries are edible according to the USDA.[36] However, the bark of cascara, another member of the genus Frangula, is toxic.[37]
The Ohlone people use the leaves to treat poison oak dermatitis.[38] The Kumeyaay people had similar uses for its bark.[38] The Kawaiisu used the fruit to treat wounds such as burns.[38] The bark has been widely used as a laxative tea by the Chumash and Costanoan.[38][39] The roots have been used by indigenous people for toothache remedies, kidney troubles, and a counteract for poisioning as well.[7] The leaves were rubbed on the skin directly to help heal infected open injuries.[39]
^ abcdFlowering Plants of the Santa Monica Mountains, revised 2000, p. 168
^ abcdefghMcMurray, N. E. 1990. Rhamnus californica. In: Fire Effects Information System. USDA FS. Rocky Mountain Research Station, Fire Sciences Laboratory.
