Family: Poaceae

Origin, Description & Uses
Tripsacum dactyloides, commonly known as eastern gamagrass, is a robust, warm-season perennial grass native to the eastern and central United States, extending south through Mexico, the Caribbean, Central America, and into northern South America. It forms large, dense clumps with broad, corn-like leaves and flowering stalks that can reach over 6 feet (2 m) tall. Eastern gamagrass is valued as a highly productive forage species for livestock due to its excellent nutritional quality and tolerance of grazing. It is also planted for erosion control, streambank stabilization, wildlife habitat, and ornamental landscaping, particularly in naturalistic gardens and restoration projects.

Risks & Threats
Although eastern gamagrass is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that raise concern for tropical island ecosystems. It is a long-lived perennial capable of forming dense stands, reproduces by both seed and vigorous clump expansion, and tolerates a wide range of environmental conditions, including periodic flooding and drought. These characteristics increase its potential to spread beyond cultivation and compete with native vegetation in suitable habitats. Because of these invasive traits, this species could detrimentally impact Hawaiian ecosystems if introduced and allowed to escape cultivation. As a precaution, Plant Pono recommends choosing a low-risk or native alternative whenever suitable options are available.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Grows in tropical climates
  
• Naturalized in Taiwan
  
• Described as a weed in some locations
  
• Pollen is a moderate allergen to humans
  
• May increase fire risk in fire prone areas
  
• Tolerates many soil types
  
• Forms pure stands in native range
  
• Reproduces by seeds and rhizomes
  
• Certain forms are apomictic
  
• Reaches maturity in 2-3 growing seasons
  
• Seeds dispersed by water, internally by grazing animals, and intentionally by people
  
• Tolerant of grazing, mowing and fire

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Provides fodder and hay for grazing animals
  
• Ornamental