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Hawaiian Wiliwili trees flower for the first time at Kahanu Garden

Nearly 15 years ago, an invasive gall wasp (Quadrastichus erythrinae) from Africa hitchhiked to Hawaii and spread like wildfire, nearly eliminating Hawaii’s native Wiliwili (Erythrina sandwicensis) forests in just a few years. Thankfully, a specific parasitoid wasp released by the Hawaii Department of Agriculture in 2008 has helped mitigate the damage of the invasive gall wasp, and statewide Wiliwili conservation efforts are beginning to show promising results.

Erythrina sandwicensis
Erythrina sandwicensis at Kahanu Garden

Saving Seeds

During the height of the gall wasp outbreak, NTBG Staff and conservation partners collected Erythrina sandwicensis seeds but were unsure if the trees would ever thrive again. This year, some of the seeds planted after the biocontrol have begun to show promising results, and many are thriving at NTBG gardens in Hawaii.

A 10-year-old tree at Kahanu Garden is showing its first flowers after years of careful nurturing from the garden’s horticultural staff. This beautiful example serves as a shining light that NTBG’s hardworking staff and conservation partners can turn the tide from the threats of extinction.

Key species in Hawaii

Hawaiian wiliwili trees are key plant species in dryland forests across the archipelago. The wood was famous across the Hawaiian islands for making crafts such as papa hee nalu (surfboards), ama (canoe floats), and much more. The vibrant red-orange seeds were strung into lei.