Family: Asparagaceae

Origin, Description & Uses
Yucca gloriosa, commonly known as Spanish dagger or mound-lily yucca, is an evergreen shrub native to the southeastern United States, where it occurs in coastal areas, sand dunes, and dry forests. It typically forms clumps of stiff, sword-like leaves and produces tall stalks of showy, bell-shaped white flowers. This drought-tolerant species is widely cultivated as an ornamental plant for its architectural form, low maintenance requirements, and ability to tolerate heat, salt spray, and poor soils. It is commonly used in xeriscaping, coastal landscaping, and other ornamental plantings in suitable climates.

Risks & Threats
Although this species is currently not known to be naturalized in the Hawaiian Islands, it does possess traits that are cause for concern and which could detrimentally impact tropical island ecosystems. Yucca gloriosa can spread through seeds and vegetative growth, tolerate a range of environmental conditions, and form persistent clumps that may compete with native vegetation in suitable habitats. In other regions where it has been introduced, it has demonstrated the ability to escape cultivation and establish outside of planted areas. Care should be taken when considering this species for landscaping in Hawaiʻi, and choosing a low risk or native alternative is recommended whenever such alternatives are available.

High Risk Traits:

• Able to grow in 6 hardiness zones, demonstrating environmental versatility
  
• Grows in tropical climates
  
• Naturalized in several European countries (no evidence in Hawaiian Islands to date)
  
• Controlled as a weed in Europe (potential environmental weed)
  
• Other Yucca species are invasive
  
• Spine-tipped leaves
  
• Unpalatable to deer and potentially other grazing animals
  
• Potentially toxic and irritant to animals and people
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively by clonal spread through rhizomes
  
• Self-compatible
  
• Spread vegetatively through garden waste
  
• Seeds dispersed intentionally by people
  
• Able to resprout after cutting

Low Risk Traits:

• Ornamental
  
• Requires specialized pollination (obligate pollination mutualism with moths in the genera Tegeticula and Parategeticula)
  
• Fruit and seed production may be limited in cultivation
  
• Fruit and seed dispersal may be limited