Invasive Pear Trees are Threatening Ohio’s Native Species

A biology professor at the University of Cincinnati is warning her colleagues that a non-native pear tree is killing off the native Ohio pear trees, and creating a variety of problems for the local ecosystem.

Theresa Culley made her announcement to botanists and biologists from several other countries at UC’s McMicken College of Arts and Sciences, during a Society of Economic Botany conference.

The Callery Pear Tree In Cincinnati

The Callery pear, which is also called the Bradford pear or Pyrus calleryana, migrated from China to Europe in the nineteenth century. A hundred years later, this pear tree started to pop up in the United States. In the 1990s, the Callery pear was a very popular tree to plant along roadways and median strips, and at one point was named “Urban Street Tree of the Year.”

The Callery pear is a beautiful tree, with white flower blossoms that bloom in the spring, and leaves that turn deep purple in the fall. The trees are known for their “lollipop” shape, and for being easy to maintain and groom.

When they first arrived in the United States, though, these trees were plagued by weak trunks. The older Callery pear trees would snap and fall over in heavy winds or snowstorms, or would split right down the middle.

Botanists learned how to grow a sturdier version of the tree, and it’s this mutated Callery that is going wild in Cincinnati’s forest areas.

The Callery secretes a chemical in the leaves it drops in the fall, which leaches into the soil and can kill other trees near it. It also holds its leaves at least a month longer than other pear trees, which creates other competitive issues and endangers other trees.