Family: Asteraceae

Dahlia pinnata (Aztec dahlia, dahlia) is a perennial herbaceous plant with a rhizome and tuberous roots. The species is native to Mexico and Central America to Columbia. Commonly used as an ornamental plant, it was cultivated by the Aztecs and was introduced to Spain in 1798. Modern dahlias are often the product of hybridization between D. pinnata and D. coccinea. As cut flowers, dahlia have a long lifespan. This plant has not been documented as naturalized in any Hawaiian Islands to date.

High Risk Traits:

• Thrives and can spread in regions with tropical climates
  
• Naturalized elsewhere (but no evidence in the Hawaiian Islands to date)
  
• Unconfirmed reports of weediness
  
• Other species may be weedy or invasive
  
• Potentially toxic to dogs if ingested
  
• May be toxic or cause skin irritation if handled
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively from tuberous roots
  
• Dahlia species capable of flowering 100-120 days from seed
  
• Seeds dispersed by gravity and through intentional cultivation

Low Risk Traits:

• No confirmed reports of negative impacts where naturalized
  
• Unarmed (no spines, thorns, or burrs)
  
• Palatable to deer and possibly other browsing animals
  
• Grows best in high light environments (dense shade may inhibit spread)
  
• Plants may be self-incompatible, or produce limited seeds when selfing
  
• Lack of specialized adaptations for long distance dispersal may limit risk of unintentional spread