Quick answer: 7 native Hawaii plants have a recorded bloom range that includes September.
7 species
- Beach naupaka Scaevola taccada · 1 states
- Florida hopbush Dodonaea viscosa · 1 states
- Ilima Sida fallax · 1 states
- Koa Acacia koa · 1 states
- Mamane Sophora chrysophylla · 1 states
- Ohelo ai Vaccinium reticulatum · 1 states
- Ohia lehua Metrosideros polymorpha · 1 states