Family: Rosaceae

Origin, Description & Uses

Rubus idaeus (red raspberry) is a deciduous, thorny bramble native to Europe and northern Asia, with closely related forms in North America. It produces arching, prickly canes, white spring flowers, and clusters of sweet, red aggregate fruits that are widely valued for fresh eating, baking, preserves, and commercial production. Red raspberry is an important temperate fruit crop grown in home gardens and farms for its flavorful berries and nutritional benefits. It performs best in cool, temperate climates and is typically cultivated under managed conditions.

Risks & Threats

Although this species is currently not known to be naturalized in the Hawaiian Islands, it does possess traits that are cause for concern. Red raspberry spreads by both seed (often dispersed by birds) and underground suckers, enabling it to form dense, thorny thickets that can outcompete other vegetation. Many species within the genus Rubus have demonstrated invasive behavior in suitable climates, particularly in disturbed or upland areas. If introduced into cooler, higher-elevation regions of Hawaiʻi, red raspberry could potentially establish and spread, negatively impacting native plant communities and restoration efforts. To help safeguard Hawaiʻi’s tropical island ecosystems, choosing a low-risk or native alternative is strongly recommended.

High Risk Traits:

• Naturalized: Naturalized in Hawaii, Australia, New Zealand, and Patagonia.
  
• Weedy Congeners: Other Rubus species (e.g., R. niveus) are notorious global invaders.
  
• Weed Status: Documented as an environmental weed in Australia/NZ and a weed in pastures/cereals.
  
• Spines: Armed with prickles that impede access and deter grazing.
  
• Unpalatable: Foliage unpalatable to most grazing animals.
  
• Host Plant: Host to serious pests and pathogens (borers, nematodes, fungi).
  
• Fire Hazard: Exhibits "Moderate-High" flammability.
  
• Thickets: Forms dense thickets that exclude other vegetation.
  
• Hybridization: Hybridizes with other Rubus species.
  
• Vegetative Spread: Spreads vigorously via root suckers; fragments resprout.
  
• Fast Maturing: Can flower and seed within two years of germination.
  
• Seed Dispersal: Seeds widely dispersed by birds and mammals that eat the fruit.
  
• Gut Passage: Seeds survive gut passage, which can enhance germination.
  
• Prolific Seed: Produces up to 14,000 seeds per square meter.
  
• Seed Bank: Seeds persist in soil for up to 60+ years.
  
• Disturbance-Adapted: Resprouts vigorously after cutting, fire, or soil disturbance.
  
• Broad Climate Suitability: Grows in wide range of temperate climates (USDA zones 4-8) and elevations.

Low Risk Traits:

• Climate Limitation: Suited to temperate regions; not adapted to tropical lowlands.
  
• Non-Toxic: Not toxic to animals or humans; fruit is edible.
  
• Shade Intolerant: Declines as forest canopies close.
  
• Self-Incompatible: Requires cross-pollination (usually by bees) for seed set.