(Sphaeropteris cooperi) HPWRA Score: 8 High Risk
Impact: Out-competes native hapu’u. Spores from Australian tree fern have been known to fly 7 miles from the parent plant. Listed on Hawai`i’s Most Invasive Horticultural Plants list.
- It grows 5 times faster
- produces 3 times more fronds
- can have up to 8 times more fertile fronds
- produces many more spores
- Shades out forest understory, limiting plant growth and germination
- Will quickly spread far and become naturalized
Description: A tree fern that grows up to 40′ tall with a skinny trunk. Fronds emerge from the trunk covered with stiff white hairs and are generally less arching than hapu’u, it looks similar to a martini glass. The trunk will be covered with triangular shaped scars caused by old fronds. The fronds look lacey, more intricate than the native hapu’u.
Comments from green industry professionals: “outgrows native tree ferns”, “Nasty plant. I’d be happy to never see it again.”, “in higher elevations it is totally invasive”, “troublesome”, “Major concern about spreading into the wild, spreads easily”