Family: Cyatheaceae

Cyathea dealbata (silver fern, ponga)  is a tree fern native to New Zealand. It is a prominent symbol of New Zealand, closely associated with the country’s sports teams and armed forces, giving it significant emotional value to its people. The name “silver fern” comes from the reflective underside of the fern’s fronds, which Māori hunters used to guide their way home at night. While there are no reports of this particular fern becoming invasive, other species in the Cyathea genus are known to be invasive. Its ability to spread through spores and thrive in tropical, shady environments means it could potentially compete with native understory plants, which is why it is placed in the category ‘evaluate’.

High Risk Traits:

• Able to grow in subtropical climates
  
• Other Cyathea species have become invasive
  
• Unpalatable to grazing animals
  
• Possible toxic properties (unverified)
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Reproduces by spores
  
• Spores dispersed by wind, possibly water, and intentionally planted by people
  
• Prolific spore production
  
• Spores may persist in the soil for >1 year
  
• Possibly able to resprout after cutting

Low Risk Traits:

• No reports of invasiveness or naturalization
  
• Unarmed (no spines, thorns or burrs)
  
• Grows on acidic soils
  
• Ornamental
  
• Not reported to spread vegetatively