(NEXSTAR) — There is something idyllic about walking down a tree-lined street, especially in spring when blooms are bursting. It’s why visitors from far and wide flock to Washington, D.C., every spring to admire the cherry blossoms.
There are some blooming ornamental trees that, while impressive, have been found to be menacing to native species. They’re so problematic, officials in some states have issued a bounty for it.
The species, the Callery pear tree, has a complicated origin story in the U.S. Originally imported from Asia in 1909 for the Arnold Arboretum at Harvard University, the tree was again brought to the U.S. a decade later by the Department of Agriculture to help the common pear (a non-native but naturalized species here) develop resistance against a destructive bacterial disease.
Once its ornamental value and hardiness were recognized in the 1950s, the Callery pear was used to develop cultivars, including the Bradford pear tree, according to the University of Illinois Urbana-Champaign. You may be familiar with other cultivars that have since been created, including the Cleveland Select, Aristocrat, and Redspire.
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Closeup of Pyrus calleryana tree in autumn with yellow leaves and tiny pear fruit -
An aerial shot of a Callery pear tree with its white blossoms against a cloudy sky -
Callery pear tree. Rosaceae deciduous tree. White flowers bloom in spring and produce fruits about 1 cm in size in summer. It is designated as an endangered species. -
Dense white blossoms cover the branches of a flowering Callery Pear tree (Pyrus calleryana), an ornamental species introduced from Asia that has become invasive across much of the eastern United States. Known for its striking spring blooms and fast growth, this tree has escaped cultivation and now spreads aggressively, outcompeting native flora and altering natural habitats. Its cultivars, such as the Bradford Pear, were once popular in landscaping but are now discouraged due to ecological impacts. This image serves as a visual reminder of the importance of planting native species and protecting biodiversity for future generations. -
A callery pear tree is pictured on Monday, April 23, 2018. Photo by Natalie Kolb (Photo By Harold Hoch/MediaNews Group/Reading Eagle via Getty Images) -
A Callery pear tree is seen in Auburn, Ga., on Sunday, March 13, 2021. A stinky but handsome and widely popular landscape tree has become an aggressive invader, creating dense thickets that overwhelm native plants and bear four-inch spikes that can flatten tractor tires. (AP Photo/Alex Sanz) -
A callery pear is seen in Johns Creek, Ga. on Sunday, March 13, 2021. A stinky but handsome and widely popular landscape tree has become an aggressive invader, creating dense thickets that overwhelm native plants and bear four-inch spikes that can flatten tractor tires. (AP Photo/Alex Sanz)
It was believed, initially, that the trees were not able to reproduce, which experts later found to be inaccurate as the species found a way to cross-pollinate because of the cultivars, Shad Hufnagel, Forest Health Coordinator for the Kansas Forest Service, told Nexstar’s KSNW.
While the pear trees have many apparent benefits — they grow quickly, can adapt to different regions, tolerate droughts and pollution, produce a dazzling bloom, and form a symmetrical shape — the Callery is less than desirable.
They typically have dense growth and thorns, per the USDA, which can prove detrimental to equipment and livestock that encounter them. Their ability to grow among pine plantations “can impede some forest management practices,” while their dense growth can block out native species. The Callery pear trees are also known to be weak, causing them to be damaged by storms frequently, experts note.
And yet, there’s something worse about them: their odor.
“The fragrance of Callery pears has been described as smelling like dead fish, vomit, urine, and other undesirable things,” Ken Johnson, a horticulture educator at the University of Illinois Urbana-Champaign, wrote last year.
Nonetheless, the trees have rapidly spread across the U.S. and can be found in several states, primarily throughout the East.
Some of those states are inviting residents to annihilate the trees, oftentimes in exchange for a preferred native species or even money.
Earlier this year, the Virginia Department of Forestry offered a Callery pear exchange program, offering residents free “native, young, healthy” replacement trees for the removal of the trees from their property. Hundreds of residents, who were responsible for all costs related to removing the Callery pear tree, took advantage of the program.
Missouri’s Invasive Plant Council offered a native tree in exchange for one or more Callery pear trees in April.
The Kansas Forest Service expects to host a buyback program in the fall. Organizations in Ohio have launched bounty and exchange programs, some of which target other invasive species as well. Pennsylvania recently launched its own program to replace invasive trees and shrubs. Similar programs have been offered in South Carolina.
Several states have outlawed the Callery pear tree in their state.
Ohio became the first state to make it illegal to sell, grow, or plant the tree in 2023, followed by Pennsylvania and South Carolina in 2024. Next year, Minnesota will prohibit the tree’s sale statewide. Starting in 2027, Callery pear trees and their relatives can no longer be moved or sold within Kansas.
Callery pear trees are identifiable by their white blooms in spring, which typically come early and produce the aforementioned foul smell, the Minnesota Department of Agriculture explains. Its leaves are wavy, rounded to teardrop-shaped, and have fine teeth. Thorns can be found on branches and stems. Callery pears can also produce large crops of tiny, hard pears that are green to brown that become soft after the first frost. Come fall, the tree’s leaves will be “brilliantly colored,” if they aren’t tarnished by frost due to their late color change.
Johnson told Nexstar that while fall is the best time to do woody plant management, as trees are sending resources from the leaves back down to the roots, you can still take down a Callery pear tree now.
He recommends cutting down the tree and treating the stumps with an herbicide, and watching for suckers — stems that can grow from the base of a tree or its roots.
While it isn’t considered invasive in every state, including Illinois, and can still be purchased, Johnson noted the species does still have invasive qualities.
“Just because you can still buy it doesn’t mean you should. We know it causes problems,” he explained, noting that that is true for all the cultivars of the Callery pear tree. “Look for something else you want. Those spring blooms, redbuds, dogwoods, things like that, still have those nice blooms and the added benefit — at least they don’t smell bad.”