Invasive Plants Still Widely Offered for Sale in US

Study found that 61% of plants identified as invasive are available to gardeners.

nursery cart with plants

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A new study from the University of Massachusetts, Amherst, has determined that many nurseries, garden centers, and online retailers are still offering invasive plant species as ornamental plants for gardens in the United States. Since invasive plants can pose a major threat to native ecosystems, this is an issue that needs to be tackled to prevent further ecological harm. 

Invaders for Sale

This new study, titled "Invaders for sale: the ongoing spread of invasive species by the plant trade industry," was published in the scientific journal Frontiers in Ecology and the Environment. It is authored by Evelyn M. Beaury, Madeline Patrick, and Bethany A. Bradley. 

Utilizing nursery catalogs and search engine data, the ecologists found that of the 1,285 species of plant identified as invasive in the US, 61% are still available to home gardeners through the plant trade. This includes 50% of state-regulated species, and 20% of those classified federally as noxious weeds, which are illegal to grow or sell across the US.

Invasive species were found to be on sale in all of the lower 48 states. No fewer than 1,330 different vendors were offering invasive species as ornamental garden plants. This included major online marketplaces like Amazon and eBay, as well as smaller outfits. This is concerning, since users can easily ship plants across state borders, likely without consequence. 

Current Protective Framework Is Not Working

Lead author on the study, Evelyn Beaury, was emphatic in a press release: "Once we’ve recognized that an ornamental plant can be invasive, we would hope that commercial sales of that species would stop. But our findings show that our current framework for removing invasive plants from plant trade isn't working."

Bethany Bradley, senior study author and professor of environmental conservation, was clear in her condemnation: "We’ve known for decades that many gardening and landscaping plants are invasive, but we’ve done little to stop propagating them. We can do better."

An online seller, who spoke to Treehugger but wished to remain anonymous, admitted that selling invasive plants was widespread in the industry, stating that they were not surprised by these findings. 

"One problem is that people in the trade are not really clear on what is regulated and what is not. The regulations vary from state to state, and at federal level. Someone might shop across state boundaries and invasive plants enter a state. Breeders make claims but we don't always know for sure if a plant will be invasive. There's no joined-up thinking. If there is a demand from consumers, plants are going to be sold."

Cogongrass, a federally listed invasive plant, which can still be found for sale in many nurseries. leodaphne/Getty Images

Preventing Ongoing Propagation and Sale of Invasive Plants

The study authors state that regional regulation and outreach to growers and consumers is required to prevent the ongoing propagation and sale of plants known to be invasive in the US. They noted that remedies should include making sure that regulations are better coordinated from state to state, and at a national level. They also noted the importance of providing growers with clear and transparent information. 

Beaury noted that there are certain barriers to effective enforcement, but said, "We’ve already heard from state regulators that have used our results to follow up with growers selling invasive species. This is great news, and if we want to continue to protect native ecosystems, regulators and managers need more resources to do so."

Will enforcement work? The anonymous seller was dubious. 

"It is so easy these days for random sellers to pop up online, so enforcing regulations is difficult. Stopping those selling invasive plants is an uphill battle. I really don't think things will change until consumers do. The most important thing is making sure the public are aware of invasive plants and how much damage they can do in certain areas to the ecology."

The Federal Noxious Weed Act identifies 105 plants which are considered the greatest threats to US natural resources. Most states have their own lists of the worst invasive plants, and other non-native plants are flagged and managed by federal or state agencies or conservation groups. 

As the plant seller told Treehugger, "Gardeners have to wake up and stop buying the most dangerous species. If that does not happen, I don't think things are really going to change."

View Article Sources
  1. Beaury, Evelyn M., et al. "Invaders for Sale: The Ongoing Spread of Invasive Species by the Plant Trade Industry." Frontiers in Ecology and the Environment, 2021, doi:10.1002/fee.2392

  2. "Federal Noxious Weed List." United States Department of Agriculture.