Family: Ulmaceae

Origin, Description & Uses
Ulmus parvifolia, commonly known as Chinese elm or lacebark elm, is native to eastern Asia, including central and southern China, Vietnam, Korea, Japan, and Taiwan. It is a medium-sized deciduous to semi-evergreen tree valued for its graceful arching form, small glossy leaves, and attractive mottled bark that peels to reveal patches of gray, green, orange, and brown. Chinese elm is widely planted as a shade tree, street tree, and specimen tree because of its tolerance of heat, drought, urban conditions, and a wide range of soils. It is also a popular choice for bonsai due to its fine branching and ability to withstand repeated pruning.

Risks & Threats
Although Ulmus parvifolia is not currently known to be naturalized in the Hawaiian Islands, it possesses traits that are cause for concern and could detrimentally impact tropical island ecosystems if it escapes cultivation. The species produces abundant wind-dispersed seeds, can establish in disturbed habitats, and has become naturalized or invasive in several regions outside its native range. Its adaptability to diverse environmental conditions and ability to reproduce readily increase the likelihood of spread into natural areas, where it could compete with native vegetation and alter ecosystem structure. Because of these risks, Plant Pono recommends choosing a low-risk or native alternative when suitable options are available, particularly for landscapes near natural or undeveloped areas.

High Risk Traits:

• Broad climate tolerance (USDA zones 4–10)
  
• Naturalized beyond native range (e.g., California)
  
• Documented environmental weed (invades wetlands, riparian areas, native communities)
  
• Congeneric weeds present (U. pumila is invasive)
  
• Shade tolerant
  
• Tolerates wide range of soil types
  
• Produces viable seed
  
• Hybridizes naturally
  
• Reproduces vegetatively via runners and sprouts
  
• Wind-dispersed seeds
  
• Water-dispersed seeds
  
• Intentionally planted widely as ornamental/street tree
  
• Seeds abundant and can be unintentionally dispersed from trafficked areas
  
• Resprouts vigorously after cutting or coppicin

Low Risk Traits:

• No spines, thorns, or burrs
  
• Not bird-dispersed or externally animal-dispersed
  
• Not toxic to animals or humans (though pollen causes moderate allergies)
  
• No evidence of reproductive failure in native habitat