Family: Rhamnaceae
Frangula californica, commonly known as California coffeeberry or , California buckthorn is a versatile evergreen shrub or small tree native to western California. It typically grows between 3 to 6 feet tall but can reach over 12 feet under favorable conditions. The plant features red-tinged twigs and ovate to elliptic leaves with prominent veins. In late spring to early summer, it produces small greenish-yellow flowers, followed by juicy drupes that ripen from green to red to black, each containing two seeds resembling coffee beans. These fruits are a food source for birds and other wildlife. California coffeeberry thrives in various habitats, including oak woodlands and chaparral, and individual plants can live for 100 to 200 years.
It is reported to be naturalized in upper elevations of Hawaii Island, where its dispersal by birds and adaptation to and tolerance of fire and browsing could allow it to spread into and compete with native forest and shrubland ecosystems.
High Risk Traits:
- Broad elevation range
- Naturalized in the Pohakuloa area of Hawaii Island
- Other Rhamnus species have become invasive
- Fire-adapted and may contribute to fuel load and increase fire risk in fire prone ecosystems
- Shade tolerant (could establish in more intact native communities)
- Tolerates many soil types (not limited by substrate)
- Reproduces by seed
- Reaches maturity in 2 years
- Seeds dispersed by birds, potentially other frugivorous animals, and through intentional cultivation
- Tolerates and resprouts after browsing and fire
Low Risk Traits:
- Unarmed (no spines, thorns, or burrs)
- Palatable to animals
- Not reported to be toxic
- Short-lived seeds (ca. 9 months) unlikely to form a persistent seed bank
- Herbicides may provide effective control
