City Trees

Reverted pear volunteers can be dangerously thorny. Photo by Brett O'Brien In an article printed in the 2008 Sept/Oct issue of City Trees, I described the Columbia, Missouri Parks and Recreation Department's efforts to confront the alarming spread of invasive Callery pear hybrids in our community with a campaign we called "Stop the Spread!" It has been nearly a decade since the campaign began and now is probably an appropriate time to share an update. The "Stop the Spread!" campaign's primary focus was to raise awareness of the Callery pear problem in Columbia, and on that level I believe we were successful. We originally began with brochures and posters but I think we reached many more people with our City website and a video our creative City staff produced. The Missouri Department of Conservation (MDC), who origi- nally helped fund the campaign with a grant in 2007, gave the campaign another boost in 2011 by publishing in their Missouri Conservationist Magazine a very affirmative "Stop the Spread!" article by MDC Regional Community Forester Ann Koenig. The highly acclaimed Missouri Conservationist Magazine reaches a very large and broad audience, and this article is how many Missouri residents first learned about the invasive threat posed by Callery pears. At this point, MDC is actively encouraging res- idents not to plant ornamental pears and currently lists Callery pear as an invasive plant pest. Although awareness of the Callery pear menace has increased in our community, unfortunately the spread of wild pears in our community continues unabated. As we explore better ways to manage the seedlings we find popping up in our parks and nature areas, we have worked with many others in search of solutions. One example is our partnership with the University of Missouri Division of Plant Sciences. The University has a weed control program in Industrial Vegetation Management (IVM); due to the growing concern in the industry about the escape of Callery pear, they were seeking sites with Callery pears that they could treat with newer herbi- cides. We had several remote areas we could provide them and in return were able to pick up some management ideas. A good example would be are switching from the "hack & spray" meth- od I mentioned in the 2008 article to a much easier and faster basal bark spray using methylated seed oil in combination with a liquid triclopyr butoxyethyl ester formulation. The issue I see brewing is that Callery pear seedlings are moving further and further into the countryside, away from the suburbs and cities from whence the problem sprang. How far and how prolifically the pears have spread nobody really knows; it's sure- ly not being fully reported. However, we can all help change that by using the Early Detection and Mapping System (EDDMapS) to document wild Callery pear seedlings we discover. EDDMapS is an easy-to-use, web-based mapping system for documenting invasive species distribution. I realize that nowadays, everything seems a crisis, but this issue is really one that should not be ignored. The sooner we all come to grips with the depth and seriousness of this invasive plant threat, the more likely we will still have ability to control its spread. —Brett O'Brien, Natural Resources Supervisor, Columbia, Missouri (right) Many city foresters feel that this is the best use of Callery pear. Photo by Steve Cothrel Reverted "fruitless" pears produce viable fruit, which birds eat and disperse everywhere. Photo by Brett O'Brien 18 City Trees

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