Family: Asteraceae

Origin, Description & Uses
Tagetes erecta, commonly known as African marigold or Aztec marigold, is native to Mexico and Guatemala despite its common name. This fast-growing annual produces large, bright yellow, orange, or golden flower heads above aromatic, deeply divided foliage. It is widely cultivated around the world as an ornamental bedding plant, for cut flowers, religious and cultural celebrations, natural dyes, and traditional medicinal uses. It is also grown in vegetable gardens as a companion plant because it can help suppress certain soil nematodes and attract beneficial insects.

Risks & Threats
Tagetes erecta is naturalized on Oʻahu and is potentially naturalizing on Maui and Hawaiʻi Island. It possesses traits that are cause for concern, including prolific seed production, rapid growth, and the ability to establish outside cultivation. As a result, it could detrimentally impact tropical island ecosystems by spreading into disturbed areas and competing with native vegetation. Because this species is already naturalized in Hawaiʻi, further planting should be avoided in areas where it is not yet widely established, and existing populations should be managed to help limit additional spread. Whenever possible, choose a low-risk or native alternative for landscaping and gardening.

High Risk Traits:

• Broad climate suitability
  
• Thrives in tropical climates
  
• Naturalized on Hawaii Island. Widely naturalized elsewhere
  
• Potential disturbance and crop weed
  
• Other Tagetes species are invasive weeds
  
• Allelopathic
  
• Toxic to dog
  
• May cause dermatitis to susceptible people
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Self-compatible
  
• Reaches maturity in <1 year
  
• Seeds dispersed by animals (internally and externally), intentionally and accidentally by people

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock (palatable despite reports of toxicity)
  
• Ornamental
  
• Requires full sun
  
• Not reported to spread vegetatively
  
• Herbicides may provide effective control