Family: Arecaceae

Origin, Description & Uses:
Sabal causiarum (Puerto Rican hat palm, palma de escoba) is native to southern Hispaniola and the Virgin Islands. It is a slow-growing, long-lived fan palm that can reach impressive heights with a stout trunk and large, costapalmate (fan-shaped) leaves. The species is well known for its strong, durable leaf fibers, which have traditionally been used for making hats, baskets, brooms, thatch, and other woven goods. In landscaping, it is sometimes planted as an ornamental palm for its bold tropical appearance, drought tolerance once established, and ability to thrive in warm coastal environments.

Risks & Threats:
Although Sabal causiarum is not known to be naturalized in Hawaii, it does possess traits that are cause for concern, including hardiness, longevity, and the production of abundant seeds that could potentially be spread by animals. In suitable climates, palms with similar characteristics have shown the ability to persist outside cultivation and spread slowly over time. For this reason, caution is recommended to ensure that it will not negatively impact Hawaii. Continued monitoring and evaluation are important to better understand its behavior in local ecosystems and to prevent potential future invasiveness.

High Risk Traits:

• Thrives in tropical climates
  
• Reported to be naturalized
  
• Genus has "weedy" traits that may contribute to its ability to become invasive
  
• Tolerates many soil types
  
• Forms thickets in native range
  
• Seeds dispersed by birds and intentionally by people

Low Risk Traits:

• Despite naturalization, no reports of detrimental impacts found
  
• Unarmed (no spines, thorns or burrs)
  
• Non-toxic
  
• Ornamental
  
• Leaves used to weave hats and baskets
  
• Not reported to spread vegetatively
  
• Slow growing and long time to reproductive maturity
  
• Will not resprout after cutting or fire