Like so many regions in New York, nearly every corner of Missouri has been hit hard with the invasive spread of Callery pear (Pyrus calleryana spp.). Callery pears are self-sterile, but it turns out they readily cross-pollinate with other cultivars. Also, the rootstock upon which a Bradford pear is grafted will sometimes sprout, eventually yielding flowers and viable pollen.

Fortunately, Missourians are often out in front with innovative approaches to urban forestry and invasive plant control. Here’s how they reduced the number of Callery pears and increased the use of native, non-invasive trees. Special thanks to Tina Casagrand of the Missouri Invasive Plant Task Force (MoIP) for her help with this post. 

Extent of Callery pear impact in Missouri.

To raise awareness about how the invasive Callery pear (Pyrus calleryana) causes harm to both regional economies and the environment, the Missouri Invasive Plant Task Force (MoIP), an inter-agency and inter-organizational resource of the Missouri Prairie Foundation’s“Grow Native!” program, partnered with Forest ReLeaf of Missouri and Forrest Keeling Nursery for a Callery pear “buy-back” event that took place on April 26, 2019.

Homeowners provide photographic evidence of a Callery pear takedown in exchange for a native, non-invasive tree. All images courtesy MoIP.

People who supplied photos of themselves with a cut-down, in-bloom Callery pear tree in their yard received a free native tree to replace it. The offer was limited to one native tree per photographic proof of cut-down tree. Participants were invited to pick up their trees at Forest Releaf CommuniTree Gardens Nursery, located in Creve Coeur Park in St. Louis.

Collage of homeowners with their cut-down pears.

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.

A homeowner pleased to be rid of a Callery pear and taking home a free, regionally native tree instead.

Although 93 native trees were provided as a trade-in to individuals happy to rid their landscapes of ornamental pears, the real value of this program was in the messaging. Over 12,500 engagements were made on social media which translated into more than 158,500 social media impressions! Radio and television also broadcasted stories about this innovative program.

This conventional and social media reach was a welcomed victory, since the urgency to alert the general public to the consequences of this rapidly spreading exotic plant pest is intensifying every day. In empty lots and along roadsides where mowing isn’t happening regularly, Callery pear takes over within just a few years. In addition to the increased economic costs of vegetation management problems in transportation and utility corridors, Callery pear progeny can cause ecological damage to native prairies and wetlands.

“Plant This, Not That” posters created by MoIP show homeowners regionally native alternatives to Callery pear.

The news may be getting worse, as recent data from Ohio suggests that forests are also at risk. University of Cincinnati Biologist Theresa Culley has warned that in some parts of Ohio, Callery pear has taken a significant foothold in many woodlots. You can follow The Culley Lab’s work on Callery pear here.

While many States in the U.S. implore residents not to plant Callery pear, this is only the second buy-back program that MoIP is aware of (Fayetteville, Arkansas was first), and it’s hoped it will serve as a model for other regions.

Homeowners were encouraged to bring their kids to the buy-back event.

Further Reading

Columbia, Missouri’s “Stop the Spread” Campaign

CITY TREES Roundtable: “Pyrus, We Have a Problem”

Missouri Invasive Plant Task Force (MoIP) Invasive Plant Assessment & Maps

Pledge to Stop the Spread of Invasive Plant Species