Family: Malvaceae

Brachychiton populneus, commonly known as kurrajong or bottletree, is a drought-tolerant tree native to Australia. It is easily recognized by its swollen, bottle-shaped trunk that stores water, glossy green leaves, and clusters of bell-shaped cream to pink flowers. Kurrajong has long been valued in its home range for shade, ornamental planting, and traditional uses; its durable fiber was used by Indigenous Australians for cordage, and its seeds can be roasted. Today it is planted in dry landscapes, parks, and streetscapes in many warm regions because of its resilience and attractive form.

In Hawai‘i, kurrajong is not widely cultivated and is not currently known to be invasive. However, like many drought-hardy ornamentals that produce abundant seeds, it has the potential to spread beyond planting sites if conditions are suitable. In other parts of the world, Brachychiton species have occasionally naturalized in disturbed areas, so monitoring is advised where the tree is planted near open, dry habitats. At present, no major ecological threats are documented for Hawai‘i, but gardeners should plant responsibly and avoid disposing of seeds or green waste in natural areas.

High Risk Traits:

• Naturalized outside native range
  
• Repeatedly introduced as ornamental
  
• Weed in urban bushland
  
• Toxic to livestock
  
• Increases fire risk (flammable litter)
  
• Tolerates varied soils
  
• Produces abundant viable seeds
  
• Hybridizes naturally
  
• Dispersed by birds & mammals
  
• Survives gut passage
  
• Resprouts after fire/damage
  
• Seed hairs irritate skin

Low Risk Traits:

• No spines/thorns
  
• Not allelopathic or parasitic
  
• Not a major pest host
  
• Not shade tolerant
  
• Not self-compatible
  
• No vegetative reproduction
  
• Slow maturation (8+ years)
  
• No persistent seed bank
  
• Herbicide controllable
  
• Not a dense thicket former
  
• Not spread by wind/water/produce contamination