Family: Asparagaceae

Origin, Description & Uses
Yucca gigantea (syn. Yucca elephantipes), commonly known as spineless yucca or giant yucca, is native to Central Mexico through Central America. It is an evergreen, tree-like succulent that can grow into a small, branching tree with thick stems topped by rosettes of long, stiff, sword-shaped leaves. Unlike many other yuccas, it lacks sharp terminal spines, making it a popular ornamental plant for tropical and subtropical landscapes. It is widely cultivated as a drought-tolerant accent plant, container plant, and indoor ornamental because of its architectural form and low maintenance requirements.

Risks & Threats
Yucca gigantea is considered a low risk plant for Hawaiʻi. Although it can produce seeds and has traits that allow it to tolerate dry conditions and persist in a variety of environments, it is not known to be invasive in Hawaiʻi or elsewhere where it has been widely cultivated. It does not appear to pose a significant threat to native ecosystems at this time, but continued monitoring is important to ensure that cultivated plants do not spread into natural areas. This species is a suitable landscape choice when planted responsibly and maintained to prevent unwanted spread.

High Risk Traits:

• Naturalized in Spain with "clear invasive behavior" (disturbed areas)
  
• Broad climate suitability (tropical, subtropical, USDA zones 9B–11)
  
• Native to multiple tropical/subtropical regions (Mesoamerica)
  
• Repeated introductions worldwide as ornamental
  
• Congeneric species are rangeland weeds
  
• Tolerates wide soil types, pH, salinity, and drought
  
• Shade tolerant
  
• Reproduces vegetatively via suckers and cuttings
  
• Deliberately spread by people as ornamental
  
• Persistent seed bank (4–5 years)
  
• Resprouts after mutilation

Low Risk Traits:

• Not an agricultural, forestry, or environmental weed
  
• No spines, allelopathy, or parasitism
  
• Non-toxic to animals and humans; low flammability
  
• Requires specialist yucca moth for pollination (limits seed set outside native range)
  
• Self-incompatible
  
• Long generation time (≥4 years to flower)
  
• Poor dispersal: fleshy fruits, not wind/water dispersed, no wildlife attraction
  
• Low seed output; not a produce contaminant