Family: Rosaceae

Rubus ‘Triple Crown’ (Triple Crown) is a thornless blackberry cultivar known for its large, sweet, and glossy black fruit. Developed by the USDA Agricultural Research Service, it thrives in a range of climates and is valued for home gardens and commercial production. The semi-erect to trailing plant can reach heights of 3–5 feet and spread up to 4 feet wide, producing firm, flavorful berries that ripen from mid-July to early August. Its vigorous growth and high yield make it a popular choice for fresh eating, baking, and preserving.

Although Rubus ‘Triple Crown’ is not known to be established in the Hawaiian Islands, it possesses traits—such as rapid growth, thornless canes, and high fruit production—that could contribute to its escape and spread if cultivated. For this reason, cultivation of this plant in Hawaii is discouraged to reduce the risk of it becoming invasive.

High Risk Traits:

• Broad climate suitability (USDA Zones 3–8)
  
• History of repeated introductions outside its native range
  
• Congeneric species are invasive weeds
  
• Produces viable seeds
  
• Self-compatible (can self-pollinate)
  
• Reproduces by vegetative fragmentation
  
• Bird-dispersed seeds
  
• Seeds survive gut passage
  
• Tolerates mutilation or pruning

Low Risk Traits:

• Not reported as naturalized or weedy
  
• Thornless
  
• Not reported to be allelopathic
  
• Does not form dense thickets
  
• Not shade-tolerant
  
• Intolerant of a wide range of soils
  
• No evidence of prolific seed production or a persistent seed bank