Welcome to the Plant Risk Evaluator (PRE) tool, designed to assess the risk of a plant becoming invasive in a given region.

PRE supports the horticultural community in evaluating the risk of new or existing ornamentals. It also supports the land management community in evaluating the risk of non-native plants that have established outside of cultivation.

A supporting climate match tool is available to help answer PRE questions about how the plant behaves in regions with a climate similar to that of the region of interest. Using the PRE tool requires training to ensure consistent scoring. To learn more about becoming a PRE screener and to request a PRE account, please email info@plantright.org. You may also want to review this video tutorial.


The PRE tool was developed for the PlantRight program, which seeks to prevent the introduction of invasive plants through horticulture. PRE is now also supported by the California Invasive Plant Council (Cal-IPC).

The initial PRE model was developed in 2015 by researchers at UC Davis and the University of Washington, with support from Sustainable Conservation, the original coordinator for PlantRight. A 2017 research project evaluated ornamental plants in Texas, Illinois, Georgia and Minnesota to test accuracy. Grants beginning in 2021 from the Western IPM Center have supported coordination in using PRE by partners in California, Arizona, Oregon, Washington, Nevada, and the Yurok Tribe.

By providing a science-based, consistent methodology, PRE provides common ground for otherwise contentious invasive plant conversations. The tool was found to be 95% accurate in predicting the invasive risk of a plant in given region. A trained assessor takes about 4 hours per plant.

Prevention is the best medicine, and PRE helps horticultural and environmental partners prevent the spread of invasive plants while avoiding regulation.