Family: Rosaceae
Origin, Description & Uses
Pyracantha koidzumii, commonly known as Formosa firethorn, is a thorny evergreen shrub or small tree native to Taiwan. It is valued in landscaping for its dense growth, glossy green leaves, clusters of white flowers, and bright red to orange berries that persist through much of the year. Because of its colorful fruit and ability to form dense hedges, it has been widely planted as an ornamental and barrier plant in gardens and urban landscapes. Birds are attracted to the berries, which can aid in spreading seeds to surrounding areas. In Hawai‘i, this species has become naturalized on Kaua‘i, Maui, and Hawai‘i Island.
Risks & Threats
Formosa firethorn is considered a high-risk species because it is naturalized in Hawai‘i and possesses traits associated with invasive behavior. Its abundant berry production, bird-dispersed seeds, dense thorny growth, and adaptability to a range of environmental conditions allow it to spread beyond cultivation into natural and disturbed habitats. Dense thickets can crowd out native vegetation, alter habitat structure, and hinder access for people and wildlife. These characteristics raise concerns about its potential to detrimentally impact tropical island ecosystems if its spread continues unchecked. Where possible, Plant Pono recommends choosing low-risk or native alternatives for landscaping and hedging purposes. In areas where Formosa firethorn is already widespread, landowners and gardeners are encouraged to manage existing plants responsibly and avoid planting it near natural areas to help minimize further spread and ecological impacts.
High Risk Traits:
- Naturalized in Hawaii, Texas, Florida, Arizona, California, Australia
- Cultivated & escaped intentionally by people
- Bird-dispersed seeds (fleshy fruits)
- Seeds survive gut passage
- Produces viable seed
- Thorns/spines present
- Tolerates wide soil conditions
- Congeneric weed (P. angustifolia invasive in Argentina)
- Host for pests/pathogens (lace bug, mites, fire blight, Phytophthora)
- Fast growth rate
- Tolerates pruning/mutilation
Low Risk Traits:
- Not shade tolerant (prefers full sun)
- No evidence of toxicity to humans/animals (berries nontoxic in tests)
- Not unpalatable to deer (may be browsed)
- Herbicide controllable (cut stump treatment)
