Invasive Ornamentals for Sale

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Weed control, management, ecology, and minutia

Author: Marie A. Jasieniuk
Posted by: Gale Perez

Published on: June 12, 2022

I read an interesting paper* recently about the sale and spread of invasive ornamental plants in the U.S. The paper describes the results of a study that examined whether identifying a plant species as invasive influenced its availability for purchase from the plant trade industry.

The authors assembled a list of 1,285 species identified as invasive or noxious in the lower 48 states from federal and state noxious weed lists, state invasive plant lists, and the Invasive Plant Atlas. They then searched for places to purchase plants or seeds of the species using Google and a database of nursery catalogs. Two classes of sellers were searched: (1) commercial nurseries with a storefront or garden center and (2) the e-commerce trade where vendors or individuals offered plants or seeds online only. For each vendor, the authors recorded their name and location and whether or not the plant was labeled as potentially invasive or was restricted from shipping to certain states.

Of the 1,285 invasives, the research showed that 61% (778 species) were available for purchase from either retail or wholesale nurseries (1,081 vendors) or online plant traders (249 vendors) with eBay offering the greatest number of species (n = 281).

About half of the invasive species (688 of the 1,285) are regulated by the federal or one or more state governments. Despite the regulations, the study showed that 50% (343 of 688) of state-regulated species and 20% (20 of 98) of federal noxious weeds continue to be sold. The federal-regulated species offered by the most vendors was a cultivar of the noxious weed cogongrass (Imperata cylindrica). The state-regulated species offered for sale by the most vendors were Chinese silvergrass (Miscanthus sinensis), common sunflower (Helianthus annuus), butterflybush (Buddleja davidii), and Japanese barberry (Berberis thunbergii). Surprisingly, all four species are offered for sale in the states in which they are regulated! In general, however, the percent of state-regulated species available for purchase was lower than the percent of unregulated species and most regulated plants were only sold outside of states where they are prohibited. Also, fewer vendors sold a species when it was regulated in multiple states.

The authors concluded that greater coordination and consistency in regulations among states at regional and national levels, and greater outreach to vendors and consumers, are needed to reduce the spread of invasive plants by the ornamental plant trade in the U.S.

*Beaury, EM, M Patrick and BA Bradley. 2021. "Invaders for sale: the ongoing spread of invasive species by the plant trade industry". Frontiers in Ecology and the Environment. 433. https://doi.org/10.1002/fee.2392

Marie Jasieniuk is a Professor and Plant Biologist with the Department of Plant Sciences at UC Davis.

Focus Area Tags: Pest Management

Tags: invasive grass (0), invasive plants (0)

Comments: 3

Comments:

by Tracy Short

on June 13, 2022 at 8:33 AM

This is a very interesting article and I agree we need some site state wide and nationally and that can be shared with all the agricultural communities via the web blog to help us with determining these invasive species and tracking them. Long overdue.

Thank you for this post

by Steve M Sanguinetti

on June 13, 2022 at 9:48 AM

For those of us who don't subscribe, is article going to be available elsewhere. As a retired landscaspe contractor I saw a lot of unadvisable plants being sold. At least pampas grass was useful for erosion control. I vaguely remember that a sterile cultivar was eventually available.

by Anne Schellman

on June 13, 2022 at 9:59 AM

Great information. The public sees an attractive plant and has no idea they may be contributing to economic, agricultural, and environmental problems in their area by installing these plants in their gardens. One of our Master Gardeners (in Stanislaus County) wrote a blog titled, "Invasive Beauties can be Deceiving." https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=52324

She references the work done by PlantRight, an organization that has made great headway in helping stop the sale of invasive plants in the nursery trade. They also suggest alternatives the nursery (or client) can choose instead. https://plantright.org/

The Statewide Master Gardener Program is involved in the nursery survey done by PlantRight, and it's exciting to see that the survey and education to nurseries is making an impact in reducing the sale of certain plants.

Reading about the number of invasive plants sold online is concerning, and something that needs to be addressed. Thank you for your timely article!