(NEXSTAR) — A stinky but handsome and widely popular landscape tree has become an aggressive invader.

Callery pears create dense thickets that overwhelm native plants and bear four-inch spikes that can flatten tractor tires.

  • This photo made available by the U.S. Department of Agriculture National Agricultural Library, Special Collections, shows USDA plant explorer Frank N. Meyer on Mount Wutai, Shanxi, China, on Feb. 25, 1908. Meyer, who died in 1918, sent an estimated 2,500 species of plants, including his namesake Meyer lemon and Callery pears, to the United States. (Courtesy of USDA via AP)

Bradford pears and other ornamental Callery pears were cultivated from an import that saved pear orchards from a deadly bacterial disease. And for decades, the decorative trees seemed near perfect, aside from a tendency to fall apart after about 15 years — and their stench.

But they cross pollinated with other ornamental varieties.

Invasive stands now have been reported in more than 30 states. Fourteen states have formally listed the trees as invasive.

In Ohio, the tree is threatening and choking out many native trees and shrubs. It’s an extremely aggressive, non-native species, according to OSU Extension.

They are so invasive that the Ohio Department of Natural Resources has made purchasing the tree illegal beginning in 2023, but experts say that move is about 20 years too late.

The Pennsylvania Department of Agriculture has decided to place a phased ban on the Callery Pear, giving nursery owners time to draw down their inventories.

Missouri’s Department of Conservation is holding a buyback program for the tree. To qualify a property owner must a photo of a cut down pear tree in order to earn a free, less offensive, replacement tree.

The Associated Press contributed to this report.