Family: Poaceae

Origin, Description & Uses
Paspalum vaginatum (seashore paspalum) is a warm-season perennial grass native to tropical and subtropical regions of the Americas. It is a low-growing, spreading grass that forms dense mats and thrives in coastal environments, especially in sandy or brackish soils. Seashore paspalum is highly tolerant of salt spray, saline soils, flooding, and heavy foot traffic, making it popular for lawns, golf courses, sports fields, and resort landscapes in coastal areas. In Hawai‘i, it has become increasingly popular as a turf grass because of its rapid growth and ability to perform well in challenging seaside conditions. This species is naturalized on Kaua‘i, O‘ahu, Moloka‘i, Maui, and Hawai‘i Island, where it is commonly found in coastal habitats and shallow brackish areas.

Risks & Threats
Seashore paspalum is naturalized in Hawai‘i and possesses traits that are cause for concern in tropical island ecosystems. Its aggressive creeping growth allows it to spread quickly and form dense, nearly pure stands that can crowd out native coastal vegetation and reduce habitat diversity. Because it tolerates salt, flooding, and disturbance, it can establish easily in sensitive shoreline and wetland environments where native species may already be under stress. The species is also capable of spreading beyond cultivated landscapes through fragments and seed dispersal. Its ability to dominate coastal habitats may alter natural plant communities and contribute to the degradation of important ecosystem functions. Although seashore paspalum is valued as a durable lawn and turf grass in coastal settings, it should be carefully managed to prevent unintentional spread into nearby natural areas. Due to these invasive characteristics, it could detrimentally impact tropical island ecosystems if left unmanaged.

High Risk Traits:

• Naturalized beyond native range (Hawaii, New Zealand)
  
• Naturalized on Kaua'i, O'ahu, Molokai, Maui, and Hawai'i
  
• Environmental weed (outcompetes native estuarine plants)
  
• Congeneric weed (other Paspalum species are weeds)
  
• Tolerates wide soil conditions (pH 5.5–8.0)
  
• Reproduces vegetatively (rapid spread)
  
• Propagules dispersed intentionally (turf grass) and by water
  
• Tolerates mowing and cultivation
  
• Low palatability to browsing animals

Low Risk Traits:

• Not a garden, agricultural, or environmental weed (in most contexts)
  
• No spines, burrs, or toxicity
  
• Shade intolerant
  
• Produces few viable seeds; no persistent seed bank
  
• Sensitive to herbicides
  
• No wind or animal external dispersal