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Photo Credit: Forest

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Photo Credit: Forest & Kim Starr

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Photo Credit: Forest & Kim Starr

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QUICK FACTS

  • HPRWA SCORE 10
  • FAMILY Fabaceae
  • CATEGORY Shrubs, Vines, & Others

Formosan koa (Acacia confusa)

A common ornamental tree that is naturalized in Hawai`i. The Division of Forestry and Wildlife of the Hawai`i Department of Land and Natural Resources has designated this species as one of Hawai`i's Most Invasive Horticultural Plants.

  • A branched tree 20 - 50 ft tall, resembles the native Acacia koa
  • Somewhat sickle shaped narrow leaves (4 in long by 1/3 in wide)
  • Flower clusters of yellow balls (1/2 in); flat linear seed pods are green to brown (4 in long by 1/2 in wide)
  • Widespread on all main Hawaiian islands except Ni`ihau; native to Taiwan and the Philippines
  • Spreads by seeds

Harm

  • Forms monotypic stands in pastures and disturbed forests
  • Shades out understory and eliminates ground cover
  • Seeds germinate profusely after fire, quickly taking over the area

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