Plants invasive to Minnesota that were purchased from online sellers. Credit: Domini Brown
Background
Understanding the pathways through which invasive species can spread is critical for assessing risk and making informed decisions about management. The Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC) uses a prioritized funding model to support research on terrestrial invasive species that pose the greatest threats. Part of MITPPC’s evaluation process includes identifying viable pathways into the state. Many of the plants prioritized by MITPPC for research are also regulated by the Minnesota Department of Agriculture (MDA) through the Minnesota Noxious Weed Law. It is illegal to sell most noxious weeds, but regulation varies by species.
As an organization that assesses risk of pathways, MITPPC assumes that if a plant can be found advertised for sale online, a viable pathway into Minnesota exists. MITPPC further assumes that if a plant is regulated by federal or Minnesota law, the pathway is considered less likely. Until this project, these assumptions had not been tested.
The ornamental plant trade is a known primary pathway of invasive plant introduction, and modern e-commerce makes it even easier. Previous research has documented the widespread availability of invasive plants through online sources, including many that ship worldwide. However, no recent studies have tested whether an online advertisement for an invasive plant results in a viable sale. Specifically, whether the purchased species matches what is received, if the plant material is alive, and if regulation affects availability.
In collaboration with the MDA, researcher Amy Morey and colleagues aimed to purchase up to five different samples of 77 different plant taxa from unique sellers and document data from the sales and items received. Of these taxa, 57 are regulated under the Minnesota Noxious Weed Law (as of 2024) and 20 are unregulated but prioritized for research by MITPPC.
Research questions
- Is an online advertisement for a plant equal to a viable pathway into Minnesota?
- Do sellers note whether a species is potentially problematic?
- Do sellers refuse a sale due to existing regulation of a species?
- If material is successfully purchased and received, is it viable?
- Are regulated species less available and/or less likely to be sold than those that are unregulated?
Purchases from online plant sales
Findings
The team found that e-commerce is a viable, easily-accessible pathway for the spread of invasive plants, despite regulation. Online sellers ranged from individuals to large businesses and resellers on a global scale.
Morey successfully purchased plant material from 82% of the taxa sought, including examples from all state regulatory categories. Samples included seeds, cuttings, rhizomes, dormant bare roots, dried flowers, and potted plants. They arrived from about 20 countries and 30 US states. In addition to the purchased plant material, hitchhiker organisms were also received (e.g., other plant species, insects, worms, pathogens).
Though fewer ads were found for some regulated species than for unregulated species, the presence of regulation did not ultimately influence the number of samples that could be received for a species. Throughout purchasing, about 8% of all attempted purchases were denied due to regulation, but then were able to be purchased from a different seller. Overall, findings suggest a lack of awareness by sellers of invasiveness and/or regulation.
Researchers are working on continuing to work on identifying and testing the viability of the plant samples received. The final data and conclusions are expected later in 2025.
This project provides valuable data on the viability of online plant sales as a pathway for invasive plants, and can assist Minnesota state agencies in regulatory efforts. It also continues to bring awareness to the role that consumers and sellers play in mitigating this complex pathway of spread.
More information
- Minnesota Noxious Weed list
- Minnesota Noxious Weed Law
- Invasive terrestrial plants, MN Dept. of Natural Resources
- Minnesota Noxious Weed book, MN Dept. of Transportation
- How to buy plants and seed online, USDA Animal and Plant Health Inspection Service
Project outreach
- North American Invasive Species Management Association annual conference, 2024
- Upper Midwest Invasive Species Conference, 2024
- Minnesota Invasive Species Advisory Council meeting, 2025
- MDA Plant Protection Division annual meeting, 2025
News and media
- U of M researchers warn on the dangers of buying invasive plants online, including buckthorn - CBS WCCO
- Talking invasive species prevention with U of M - University of Minnesota News
Invasive plants on display at the CBS Conservatory
Some of the plants received during this project are being added as a collection to the CBS Conservatory and Botanical Collection. The plant specimens will be available for academic study to students and researchers at the U of M, as well as for educational viewing by the public.