The Assessment Tool

Summary of Results

Detailed Species Results

Economic Impact Analysis

Model Development

Model Comparison

Relevant Links


Project Description

An Invasive Species Assessment System for the North Carolina Horticultural Industry was developed by Clara Trueblood as part of a Master's Thesis project in the Department of Horticultural Science at North Carolina State University.

The North Carolina Nursery and Landscape Association (NCNLA) supported the development of an invasive assessment protocol designed to systematically assess the potential invasiveness of ornamental plants suspected to affect natural areas in North Carolina.

The North Carolina protocol incorporates and builds upon elements of existing assessment models to evaluate the potential invasiveness of plant species in accordance with regional environmental conditions.

The North Carolina assessment criteria are based on a framework of weighted sets of indices that evaluate and rate:

  1. Ecological Impacts
  2. Current Distribution and Potential for Expansion
  3. Management difficulty
  4. Benefit and Value

According to the combined weighted results, the model generates a recommendation for evaluated species ranging from 'unlikely to be invasive' to ‘invasive and not recommended for use.' 

The assessment model incorporates a unique cost/benefit analysis and weighs economic benefits against the ecological risk of selling potentially invasive ornamental plants (Economic Impact Analysis).

The assessment protocol was used to evaluate the invasiveness of 25 nonnative taxa (Summary of Assessment Results).

By modifying the criteria utilized in existing assessments and tailoring the model for the North Carolina horticultural trade, we have created an assessment system unique to the nursery industry that may be completed using resources available in North Carolina.

The assessment results are intended to allow the NCNLA to advise their members regarding plants that are purported to be invasive.

For additional background information, please see the Project Scope and Justification.


This project was generously funded by the North Carolina Nursery and Landscape Association.




Created by C. Trueblood, 2009

Last updated: December 29, 2009