Family: Rosaceae
Rosa multiflora is a thorny shrub that escapes cultivation. Native to Japan, R. multiflora was introduced to China as rootstock for ornamental roses. Promoted as a living fence during the 1930s in the mainland USA, R. multiflora now occupies 45 million hectares. Several states have declared it a noxious weed. In Hawaiʻi, R. multiflora is naturalizing in the upper elevation forests near Kulani prison. The thorny shrub tends to form dense thickets that impede movement.
Description and Dispersal:
- Arching, multistemmed red-colored canes
- Compound leaflets with serrated edges
- Stiff, curved thorns
- Feathered stipuels
- White to pink flowers are produced in corymbs
- Bird dispersed seeds
High Risk Traits:
- Naturalized and noxious weed in multiple U.S. states
- Causes major agricultural damage (pastures, beef production)
- Forms dense thickets, displacing native plants
- Produces thorns
- Host for rose rosette virus
- Creates fire hazard
- Shade tolerant
- Wide soil tolerance
- Prolific seed production (up to 1 million seeds/year)
- Persistent seed bank (up to 20 years)
- Bird-dispersed; seeds survive gut passage
- Intentional human introduction
- Seed contaminant
- Tolerates fire and mutilation (resprouts)
Low Risk Traits:
- Not allelopathic, parasitic, or toxic
- Self-incompatible (obligate outcrosser)
- No wind, water, or external animal dispersal
- No vegetative spread (layering minimal)
- Well controlled by herbicides
