Family: Poaceae

Origin, Description & Uses
Paspalum notatum, commonly known as bahia grass, is a warm-season perennial grass native to South America, ranging from Peru and Brazil to northern Argentina. It is widely used in tropical and subtropical regions as a pasture grass, lawn grass, and for erosion control because of its tolerance to drought, poor soils, and heavy grazing. Bahia grass forms dense mats with spreading rhizomes and produces characteristic V-shaped seed heads. It has been introduced to many parts of the world for agriculture and landscaping and is now naturalized on Kaua‘i, O‘ahu, Maui, and Hawai‘i Island, with potentially naturalizing populations on Moloka‘i and Lāna‘i.

Risks & Threats
Bahia grass is naturalized in Hawai‘i and possesses traits that are cause for concern in tropical island ecosystems. Its vigorous growth, dense root system, and ability to spread by seed and rhizomes allow it to outcompete native vegetation and dominate disturbed areas, pastures, roadsides, and open habitats. Dense stands may reduce native plant diversity, alter habitat structure, and complicate restoration efforts. Because it tolerates a wide range of environmental conditions and can persist once established, this species could detrimentally impact sensitive ecosystems if its spread continues unchecked. When possible, choosing a low risk or native alternative is recommended, particularly in areas near natural habitats or conservation lands.

High Risk Traits:

• Broad climate suitability (cool temperate to tropical wet/dry)
  
• Naturalized in the US and Australia
  
• Naturalized on Kaua'i, O'ahu, Maui, Hawai'i; potentially naturalizing on Moloka'i & Lana'i
  
• Principal agricultural weed in the US, Uruguay, Venezuela
  
• Congeneric weeds (Paspalum spp.) are serious global weeds
  
• Allelopathic (suppresses germination/growth of other plants)
  
• Allergenic pollen (hay fever, asthma)
  
• Shade tolerant (yields higher under 50% shade)
  
• Tolerates wide range of soils
  
• Abundant, viable seed production (~9,000 seeds/m²)
  
• Persistent seed bank (≥3 years)
  
• Facultative apomixis (self-compatible)
  
• Spreads by rhizomes
  
• Deliberately spread by humans (forage, turf)
  
• Potential seed contaminant
  
• Seeds survive animal gut passage
  
• Tolerates defoliation and controlled fire

Low Risk Traits:

• No spines/burrs
  
• Not a garden, environmental, or aquatic weed
  
• Palatable and non-toxic to animals