Family: Myrtaceae

Origin, Description & Uses
Leptospermum polygalifolium (yellow teatree, tantoon) is native to eastern Australia and Lord Howe Island, where it grows as a large shrub or small tree in coastal forests and open woodlands. It is recognized for its fine, aromatic foliage, abundant small white to cream flowers, and ability to tolerate a wide range of soil and moisture conditions. In cultivation, it is often used as an ornamental landscape plant and hedge species, and it is valued for its nectar-rich flowers that support bees and other pollinators, as well as for traditional uses such as essential oil production and light timber applications.

Risks & Threats
This species is naturalized in Hawaiʻi and has the potential to spread beyond planted areas, particularly in suitable wet to mesic environments on Oʻahu. Leptospermum polygalifolium possesses traits that are cause for concern, including prolific seed production, environmental tolerance, and the ability to form dense stands that can outcompete native vegetation. Its spread could alter habitat structure, reduce biodiversity, and negatively impact tropical island ecosystems already under pressure from invasive plants. Because of these risks, it is recommended to choose a low-risk or Hawaiian native alternative when selecting plants for landscaping or restoration projects.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Naturalized in regions with tropical climates
  
• Naturalized on Oahu, (Hawaiian Islands), escaped in New Zealand
  
• An environmental weed on Oahu, Hawaiian Islands, and targeted for control
  
• Other Leptospermum species are invasive
  
• May be unpalatable relative to other plants
  
• Tolerates many soil types
  
• Forms dense stands
  
• Reproduces by seeds
  
• Hybridizes with other Leptospermum species
  
• Possibly self-compatible
  
• Seeds dispersed by wind, water and intentionally by people
  
• Prolific seed production (numbers unknown)
  
• Seeds form a persistent canopy seed bank
  
• Able to resprout from lignotuber after cutting or fire

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Ornamental
  
• Grows best in full sun (may limit spread into densely shaded forest understory)
  
• Not reported to spread vegetatively