Family: Dryopteridaceae

Origin, Description & Uses
Cyrtomium falcatum, commonly known as holly fern or house holly fern, is native to eastern Asia, including Japan, Korea, and parts of China. It is a hardy, evergreen fern with glossy, dark green fronds made up of leathery, holly-like leaflets with spiny edges. Because of its attractive foliage and tolerance of shade, drought, and a range of soil types, holly fern is widely used as an ornamental plant in gardens, landscapes, and indoor containers. It is often planted in shaded borders, under trees, or as a groundcover in low-light areas.

Risks & Threats
Holly fern is naturalized on Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi Island. It reproduces by spores and can spread beyond cultivation into forests and other natural areas. Its ability to tolerate deep shade, variable moisture conditions, and poor soils gives it a competitive advantage in native understory environments. These traits are cause for concern, as dense growth can crowd out native plants and alter forest structure. Because this species is naturalized and has characteristics that could detrimentally impact tropical island ecosystems, Plant Pono considers it high risk. Gardeners and landscapers are encouraged to choose low-risk or native alternatives to help protect Hawaiʻi’s unique natural resources.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Grows in tropical climates
  
• Naturalized on all the main Hawaiian Islands and widely naturalized elsewhere
  
• Regarded as an environmental weed in Hawaii, (where it threatens Stenogyne bifida), Bermuda, Macaronesia, Florida and Australia
  
• Unpalatable to deer, rabbits and probably other animals
  
• Shade-tolerant (capable of invading forest understory)
  
• Tolerates many soil types
  
• Reproduces by spores and vegetatively by rhizomes
  
• May hybridize with native C. caryotideum)
  
• Apogamous (able to develop a sporophyte from a gametophyte cell without fertilization)
  
• Spores dispersed by wind, water and intentionally cultivated by people
  
• Prolific spore production

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Despite weediness, valued for ornamental uses
  
• May take 5 years for to reach maturity
  
• Herbicides may provide effective control