'Non-invasive' cultivar? Buyer beware

October 7, 2011

Cultivars of popular ornamental woody plants that are being sold in the United States as non-invasive are probably anything but, according to an analysis by botanical researchers published in the October issue of BioScience. Tiffany M. Knight of Washington University in St. Louis, Missouri, and her coauthors at the Chicago Botanic Garden write that the claims of environmental safety are in most cases based on misleading demographic evidence that greatly underestimates the plants' invasive potential. What is more, the offspring of cultivars do not usually "breed true" and may be more fecund than their parents, especially if they cross with plants from nearby feral populations.

Many were once ornamental , because the characteristics that the "green" industry looks for are the same ones that make a plant potentially invasive -- being adaptable to wide range of conditions, forming dense stands good for erosion control, and having a long flowering period, for example. In recent years the nursery and horticultural industries have responded by creating cultivars of top-selling plants that produce reduced numbers of viable seed and are advertized as "safe to natural areas." Such cultivars of Japanese barberry, buckthorn, and burning bush are now widely sold, as they avoid bans on growing .

Yet simple population modeling demonstrates that reductions of even 95 percent in the number of viable seed will leave a long-lived species quite capable of spreading -- and many of the new cultivars do not achieve even that much of a reduction. More sophisticated modeling would likely reveal even stronger invasive potential of the "safe" cultivars. Knight and her co-authors conclude that only completely sterile cultivars can be considered truly safe without further testing, and that other types should be tested for breeding true and having a low growth rate before they are sold as non-invasive.

Explore further: Is transgenic cotton more profitable?

Related Stories

Is transgenic cotton more profitable?

February 18, 2008

Transgenic cotton cultivars were planted on almost 93% of U.S. cotton acres in 2007. Transgenic cultivars with pest-managing traits are dual-purpose products. The cultivars produce lint and seed, while the expressed propriety ...

Georgia goes bananas

February 26, 2009

Bananas, known most often as a healthy, convenient food, are also popular ornamental plants in the southern United States. Banana plants are highly prized by many as one of the most beautiful ornamentals used for creating ...

Developing alternatives to invasive shrubs

September 8, 2010

(PhysOrg.com) -- Connecticut's largest group of ornamental plant growers recently took a big step towards curtailing the spread of invasive plants in the state. In June, the Connecticut Nursery and Landscape Association announced ...

Can bedding plants thrive with recyled water?

December 30, 2010

To conserve dwindling water resources, municipalities are encouraging the use of "recycled water", municipal wastewater that has been extensively treated and deemed safe to reuse for irrigation and other purposes. Using recycled ...

Recommended for you

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Ancestral background can be determined by fingerprints

September 28, 2015

A proof-of-concept study finds that it is possible to identify an individual's ancestral background based on his or her fingerprint characteristics – a discovery with significant applications for law enforcement and anthropological ...

Bat species found to have tongue pump to pull in nectar

September 28, 2015

(Phys.org)—A trio of researchers affiliated with the University of Ulm in Germany and the Smithsonian Tropical Research Institute in Panama has found that one species of bat has a method of collecting nectar that has never ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.