Stinky but handsome and widely popular landscape trees have spawned aggressive invaders, creating thickets that overwhelm native plants and sport nasty four-inch spikes. Bradford pears and 24 other ornamental trees were developed from Callery pear trees—a species brought to America a century ago to save ravaged pear orchards. Now, their invasive descendants have been reported in more than 30 states, per the AP. “Worse than murder hornets!” was the tongue-in-cheek title of a US Department of Agriculture webinar in 2020 about Callery pears, including the two dozen thornless ornamental varieties sold since the 1960s.
“They’re a real menace,” said Jerrod Carlisle, who discovered that four trees in his yard and one at a neighbor’s had spawned thousands on 50 acres in Otwell, a community of about 400 in southern Indiana. Indiana is among 12 midwestern and western states that have reported invasions, though most are in the South and Northeast. Without regular maintenance, fields near seed-producing trees can be covered with sprouts within a couple of years, said James “JT” Vogt, a scientist at the US Forest Service. “If you mow it, it sprouts and you get a thicket," he said. “If you burn it, it sprouts, too.” Seedlings only a few months old bear spurs that can punch through tractor tires.
The stench wafting from the tree's billows of white blossoms has been compared to perfume gone wrong, rotting fish, chlorine, and a cheese sandwich left in a car for a week. Some states, including Missouri and Alabama, are asking homeowners and landowners to stop planting them or to cut existing ones down and apply herbicide to the stumps. Several, such as North Carolina, offer free native trees to landowners who provide photos proving they have cut down Callery pears on their property. (Read more on the history of the trees and modern efforts to curb their spread.)