Weed risk assessments and Plant Pono program push nurseries to phase out high‑risk species

Hawaii’s weed risk assessment program and the Plant Pono outreach effort aim to reduce introductions of invasive plants by combining science-based evaluations with voluntary nursery endorsements and public education.

Chuck Camara, HISC’s weed risk assessment specialist, told lawmakers the tool used in Hawaii is a 49-question assessment adapted from Australia and New Zealand that places plants into low, moderate and high risk categories. “The results are also transparent… All the results are published and available online,” Camara said, noting that 2,375 species have been assessed to date and that results inform county planting plans, state permitting prioritization and federal programs.

Camara described Plant Pono as a public-facing website and endorsement program that encourages nurseries to follow best management practices, stop selling species on an agreed “no grow” list, and provide planting guides tailored to local ecological conditions. He cited Big Island data showing a drop in participating nurseries selling invasives from 23 in 2017 to eight in 2024 and reported steep increases in Plant Pono and PlantPono/weed-risk web traffic since 2021.

Program staff emphasized that weed risk assessment results are non‑regulatory and should not be used alone to ban widely valued crops; instead they recommended a deliberative process that weighs economic and ecological costs before pursuing restrictions. Still, speakers urged updating Hawaii’s noxious weed rules (last revised in 1992) and said HISC’s long-term goal includes shifting toward a “clean list” model—prohibiting introductions unless a species is proven low risk—particularly for species that threaten keystone native flora.

At the briefing, Camara also recommended combining voluntary incentives with targeted regulatory tools (for example, surcharges or updated rules) where voluntary measures fail to stop high‑risk sales.