Contact: Tina Casagrand, [email protected]
Callery pear’s white blooms most obvious this time of year. This highly invasive tree threatens native wildlife and causes difficulties for private and public landowners.
Missouri (April 8, 2018)—Call it the Jekyll and Hyde street tree of Suburban America. Once a favorite tree to plant for its profusion of spring blossoms and brilliant fall foliage, the Callery pear—also referred to as Bradford pear—is now becoming known as a weak-wooded, smelly, thorny nuisance.
Callery pear limbs generally grow vertically, forming a pyramid or egg shape. In early April, very dense clusters of white flowers cover the tree before leaves form. In maturity, they reach heights of 30 to 40 feet. Property owners are encouraged to cut the trees during spring (when they are easy to identify) as a means to reducing populations from spreading in unwanted areas. (Click here for details on how to treat cut stumps with herbicide.)
When non-native Callery pear cultivars cross pollinate, the hybrid offspring become invasive, meaning they are aggressive trees whose presence causes or is likely to cause economic harm, environmental harm, or harm to human health.
“From China to our backyards and parks, Bradford pears brought white flowers and fall colors to many parts of the U.S. for decades,” said Dr. Reid Smeda, Professor in Weed Science from the University of Missouri. “Recent introduction of other cultivars led to hybridization and resulted in fertile seed production. Through foraging birds, escaped Callery pear populations have exploded, and threaten native biodiversity as these invasive trees steadily march into our native grasslands and forested areas, and are even becoming a headache for land developers. Don’t let the beauty of this beast fool you,” Smeda said.
Dr. Smeda is a member of the Missouri Invasive Plant Task Force (MoIP). An inter-agency and inter-organizational resource of the Grow Native! program, MoIP’s principal goal is to make early detection and control of invasive plants a higher statewide priority. In February 2019, MoIP unveiled its statewide Invasive Plant Assessment that ranks the impact, abundance, and trend in abundance of 142 different invasive plant species.
The assessment found that, in regions with sufficient data, Callery pear’s presence imposed moderate to severe environmental degradation on the landscape, and its range is increasing at moderate to severe rates. The MoIP website offers resources on how to control this highly invasive woody species; and provides resources on native alternative trees to plant instead.
On April 26, 2019, as part of its 2019 Callery pear awareness campaign, MoIP will partner with Forest ReLeaf for a Callery Pear Buy-back offering. People who supply a photo of themselves with a cut-down, in-bloom Callery pear tree in their yards will receive a free native tree to replace it, one per household (or per cut-down tree), at Forest Releaf CommuniTree Gardens Nursery in Creve Coeur Park (2194 Creve Coeur Mill Rd) on April 26 from 9 a.m. to 4 p.m., while supplies last.
The organizations caution owners to properly identify Callery pear against other native, noninvasive trees with white flowers blooming in April, including serviceberry, wild plum, and dogwoods. This web page from the City of Columbia offers photos of native trees for comparison.
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The Missouri Invasive Plant Task Force (MoIP) is a resource of Grow Native!—a 19-year-old native plant marketing and education program serving the lower Midwest. Grow Native! is administratively housed by the nonprofit Missouri Prairie Foundation. For more information about MoIP, visit www.moinvasives.org or call 417-299-1794; for more on the Grow Native! program, or the Missouri Prairie Foundation, visit grownative.org or moprairie.org
Forest ReLeaf of Missouri is an independent, nonprofit organization dedicated to inspiring volunteer efforts in planting and caring for our trees and forests, particularly those in our cities and towns. Since 1993, the organization has provided over 200,000 native trees for plantings throughout the region. www.moreleaf.org