Information Needed on Callery Pear Cultivars Escaping in New York

The Bradford Pear, a cultivar of the Callery Pear (Pyrus calleryana), is a popular landscaping tree in the United States. It is a widely used street tree and parking lot tree in most areas of New York State although it is not cold hardy below -28 degrees thus restricting its use in northern New York. The species was originally imported from China to serve as a rootstock for the edible pear when it became susceptible to fire blight in the early 1900s. It was also found to be a good tree for landscaping because of its compact form, profuse white flowers (but with a acrid smell), absence of fruit, and ability to survive in many harsh environmental conditions including along streets and parking lots. Eventually it was found to be susceptible to breakage after about 15-20 years and many other cultivars of the Callery pear were developed to use instead of the Bradford Pear. Even though the Bradford Pear is self-incompatible and does not produce fruit, it is compatible with other cultivars and with the original Callery pear rootstock that often grows into mature trees if left unattended. Fruit from these cultivar crosses are eaten by birds (mostly invasive starlings) and have been germinating in natural areas where they have become invasive. In the Midwest and Southeast they have become a serious problem in natural open habitats.

Is it invasive in New York State? On Long Island there are some reports that show this tree to be spreading into open natural areas.

We need to have more information and evidence that fertile trees are escaping into natural areas in New York so we can evaluate the invasiveness of this species here.
We would like to know the following:
– in what habitats does it occur?
– does it create a new vegetation layer in the habitat?
– does it have an impact on other species?
– are there large dense stands over one quarter acre?
– are the trees primarily in disturbed, weedy areas or in undisturbed areas with few weeds?
– is germination occurring?

If you have a suspicion or know of any places in New York where this tree has escaped into natural areas, please let us know by sending an e-mail to Steve Young   smyoung@gw.dec.state.ny.us   Thank you.

For more articles on its invasiveness see:

http://weblogs.baltimoresun.com/features/gardening/2010/04/bradford_pear_trees_1.html

http://www.invasive.org/browse/subinfo.cfm?sub=10957

http://grumpygardener.southernliving.com/grumpy_gardener/2011/02/i-just-hate-bradford-pear.html

Use as a street tree. Photo invasive.org

Trees escaping into the wild. Photo invasive.org

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One Comment on “Information Needed on Callery Pear Cultivars Escaping in New York”

  1. Michael D. Byer Says:

    I have been working in the field in NYC for about 20 yrs now. Although there are lots of P. caleryana street and landscape trees around the city, I have never seen an escaped one. True, there are vast areas within the five boroughs that I have never visited, so I cannot claim any expertese on the subject. I’ll forward this to a few other amateur and professional botqnists I know.


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