Family: Malvaceae

Origin, Description & Uses:
Lagunaria patersonia, commonly known as the Norfolk Island hibiscus or cow itch tree, is native to eastern Australia, including parts of Queensland and New South Wales, as well as Norfolk and Lord Howe Islands. This evergreen tree is valued for its attractive, glossy green foliage and showy pink to mauve hibiscus-like flowers, followed by woody seed capsules. It is widely planted in warm climates as an ornamental and shade tree, especially in coastal landscapes due to its tolerance of salt spray, wind, and poor soils. Its neat growth form and resilience make it a popular choice for streetscapes and gardens.

Risks & Threats:
Although Lagunaria patersonia is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that raise concern for tropical environments. It can produce abundant seeds and thrives in coastal and disturbed habitats, conditions common across Hawaii. In other regions, it has shown the ability to spread beyond cultivation, potentially forming dense stands that could compete with native vegetation. Additionally, the tree’s seed pods contain irritating hairs that can pose a nuisance to people and animals. Given these risks, planting this species is discouraged. Instead, consider choosing a low-risk or native alternative better suited to Hawaii’s ecosystems to help prevent unintended ecological impacts.

High Risk Traits:

• Naturalized outside native range
  
• Environmental weed (outcompetes coastal species)
  
• Forms dense thickets
  
• Tolerates wide range of soil conditions
  
• Produces viable seed
  
• Seed bank persists 1–5 years
  
• Propagules dispersed intentionally by people
  
• Propagules water-dispersed
  
• Prolific seed production (masses of seed pods)
  
• Toxic to humans (seed poisonous; pod hairs cause skin irritation)
  
• Host for pests (e.g., Nectria hoheriae, olive scale)
  
• Fire-resistant (may tolerate fire-prone ecosystems)

Low Risk Traits:

• No spines, thorns, or burrs
  
• Not allelopathic (unknown)
  
• Not unpalatable to grazing animals (palatable, but grazing prevents regeneration)
  
• Not toxic to animals
  
• Not shade tolerant (requires full sun)
  
• No vegetative fragmentation (does not resprout or produce root suckers)
  
• Not bird-dispersed (non-fleshy capsules)
  
• Can be controlled by herbicides (e.g., glyphosate)