Coffeeberry - Frangula californica

   

Umbels of tiny flowers

Few California native plants are as versatile as the California coffeeberry. The shrub grows naturally in a neat shape that looks like the work of skilled gardener, so it is appropriate in formal or informal garden designs. Several selections of Frangula californica exist that vary in size from ground cover to large shrub, so there is one for every garden! The shrub is versatile too. It grows in either sun or shade, and naturally occurs in wide range of habitat types along the western side of California at elevations below 3,500 feet. It is found in alkaline soils in coastal sage scrub, chaparral, and in oak woodlands, and mixed-evergreen forested areas throughout the state, and extending up into the Siskiyou Mountains of southwestern Oregon. In Southern California the shrub is limited to coastal areas with greater water availability and less summer heat.

Description
In full sun, coffeeberry is an evergreen large mounding shrub, from 6-15 feet in height and equally as wide. In shade, the growth habit is more open and sprawling. Alternate oval leaves, that are 1-3 inches long, grow on reddish-tinged flexible branches and petioles. Leaves on coastal plants tend to be thin, and green on both sides of the leaf. Leaves of more arid location shrubs are thicker, curl under at the margins, and are often whitish and hairy underneath to conserve moisture. The green of the leaves is unique and almost a flat blue-green, with some plants having a blackish-green cast. Leaf midribs are strongly raised and the veins curve at the margins towards the leaf tips. New growth twigs and petioles are highly colored.

Raised midrib and curving veins

Wildlife Gardening
Tiny greenish star-shaped flowers in umbels of 5-60 flowers are relished by bees, flies, butterflies and visited by hummingbirds. Ripened fruits are devoured by many bird species. Coyote and deer also eat the fruit. The fruit is a drupe containing, most commonly, two seeds, with the subspecies, occidentalis, having three seeds. Fruits of various colors, from yellow to red to purple/black can be found on the shrub at one time, giving it a festive appearance, almost like multi-colored Christmas ornaments. The shrub is also the host plant for the larvae of Pale Swallowtail butterflies. My blooming coffeeberries are very popular with non-native honey bees, but they are important for native bees as well, one study found six native bees species visited the plant. If wildlife gardening is your focus, this plant should be at the top of your list.

Multi-colored fruit

Honeybee on flowers

Subspecies and Genus Changes
California coffeeberry was recently changed from Rhamnus california to Frangula californica because of new DNA evidence. Recent findings support genus Frangula as a monophyletic genus. The genus Frangula differs from the genus Rhamnus as it has five-petaled flowers, buds without bud scales, alternate leaves, and spineless branches. Rhamnus has (but not always)
four-petaled flowers, bud scales, alternate OR opposite leaves, and branches with spines. Coffeeberries share allegiance in the Rhamnaceae family with Ceanothus. Frangula californica has six subspecies listed in CalFlora with Frangula californica ssp. californica occurring coastally, and other subspecies in more arid or in serpentine (ultramafic) soils that are low in calcium and rich in magnesium and iron. In San Diego County the subspecies Frangula californica subsp. tomentella is more common inland. The underside of the leaves of this subspecies are covered in fine, soft whitish hairs (tomentose). This hairy adaptation slows water loss in transpiration by retarding the movement air across the leaf surface. Strict classification of the plants is complicated by common occurrence of interbreeding throughout the state.

Ethnobotany
Chumash Indians of Southern California used the aged bitter bark and berries of Frangula californica for purging and as a treatment for constipation. Major chemical constituents of the plant are anthraquinone glycosides, which are a class of phenolic compounds that work by increasing the action of smooth muscle in the large intestine. The Ohlone and Kumeyaay peoples used the leaves for poison oak dermatitis. The fruits were eaten fresh and raw or sun-dried by some tribes, while other tribes considered them toxic. Kawaiisu Indians used the leaves, berries and sap to staunch bleeding and to heal infected skin wounds.

Propagation
Coffeeberry is easy to propagate by fresh seed. Dry seed requires cold stratification. Collect mature fruit, identified by the deep black color, in the summer through fall and squeeze out the seeds from the pulpy fruit. Depending on the subspecies, individual fruits will have 2-3 hard brown seeds. Soak cleaned seed up to 24 hours and plant. Cotyledons will appear in 4-6 weeks. The germination rate is very high for fresh seed, although, the plants grow slowly once they have sprouted. Keep in mind that plants from named cultivars may not come true from seed.

Cultivars
Several cultivars for the coffeeberry were developed. I grow a native species (probably subspecies californica), and two cultivars, 'Eve Case' and 'Leatherleaf.' After three years in my garden in full sun, 'Leatherleaf' is about 3 feet high and 5 feet wide. 'Eve Case' has a more scandent, open habit and is a little taller at 4 feet and 5-6 feet wide. The native coffeeberry in my garden is easily 6 feet tall and wide and flowers more heavily. This is probably because it is this plant is in a slightly shady place with richer soil that gets more irrigation.

'Eve Case' 

'Leatherleaf'

According to the books I consulted, 'Seaview', and 'Little Star' have low dense growth that is very controlled and lends itself to a neat formal gardening style. 'Mound San Bruno' is dense but matures taller at 5 feet. When used as a foundation plant, the regular forms of this plant juxtapose well with more exuberant California natives as a place to rest the eye. Larger cultivars, mentioned previously, are 'Eve Case' which grows to 8 feet tall and 'Leatherleaf' which matures at 5 feet. 'Leatherleaf' has especially dark green foliage and is used effectively as a foil against white or gray-foliaged native plants like Artemisia californica 'Canyon Gray.' These plants lend themselves to pruning, if necessary, and can be used as an informal screen or hedge.

Care
Though considered semi-drought tolerant, in San Diego, coffeeberry would like supplemental irrigation. Ideally, 25 inches of rainfall is best for this plant. Mulch and a little shade would also benefit this plant further from the coast. Coffeeberry is best in well-draining soil and can tolerate more irrigation than other California natives, especially if planted in faster-draining soils. Moist, clay soils are problematic for this plant. It is reassuring to note, that after a fire, these plants resprout quickly from dormant buds in the root crown. Rangy growth can be pruned back with no problem.

The books says coffeeberry blooms in summer, but in my garden, they are blooming now on the first day of Spring and are covered in honey bees and flies. Many people who visit, comment on the profusion of birds in my garden and it is because I plant shrubs like the coffeeberry. Happy Spring!