Most of you know my professional opinion about ornamental pears: invasive, high-maintenance, little benefit to our overall urban forest canopy. The invasive part has me the most concerned and we are starting to see it here in NW Ohio. My colleague, Wendi VanBuren in SW Ohio sums it up very nicely below.
I always send this email message out this time of year when the flowering Callery pear trees are in bloom so you can see just how invasive they have become along our streets and in our parks. As you drive and walk around this next week or two, pay attention to the white flowering trees along the highway and your favorite hiking trail. These are all invasive flowering Callery pear that have seeded themselves in and are outcompeting even invasive bush honeysuckle in many places. Make note of where they are so you can plan efforts on their control in this year’s work plan. Like invasive bush honeysuckle, they are much easier to remove when they are smaller and less established.
ODNR Division of Forestry – Page 12 http://forestry.ohiodnr.gov/portals/forestry/pdfs/invasives/InvasivePlantsofConcern.pdf
The Beginning of a New Invasive Plant: A History of the Ornamental Callery Pear in the United States http://bioscience.oxfordjournals.org/content/57/11/956.full