Bradford pear trees look pretty and smell like rotten fish. They're also illegal. But why?

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01-04-2025

It's officially spring in Greater Cincinnati, meaning you've probably seen white-flowering Callery pear trees blooming all over the city.
The Callery pear tree − also known as the Bradford pear tree − is a common non-native tree that has grown in popularity due to its pretty foliage. From white flowers in the spring to purple leaves in the fall, Callery pear trees are an attractive signifier that the area is entering a new season.
But did you know it's actually illegal to plant, grow and sell Callery pear trees in Ohio due to their invasive nature?
So why are they banned in Ohio? And why do they smell? Here's what you should know.
Callery pear trees (Pyrus calleryana) were introduced by the United States Department of Agriculture as ornamental landscape trees in the mid-1960s, USA TODAY reports.
According to the Ohio Department of Natural Resources, the Callery pear was introduced in breeding programs in the U.S. because it was known to resist fire blight, a disease affecting pear and apple trees. It then quickly became a favorite in landscaping because of its adaptability, flowering, fall color and rounded crown.
ODNR says Callery pear trees have numerous cultivated varieties that can cross-pollinate with each other and produce viable fruit. The most commonly used cultivar is Bradford. Other common cultivars include Cleveland Select, Autumn Blaze, Chanticleer and Whitehouse.
The Callery pear tree is an ornamental species native to China and Vietnam.
The Callery pear species is a medium-sized tree that reaches a height of up to 40 feet, per the Western Pennsylvania Conservancy. The tree has smooth bark that is grayish brown and becomes scaly with age.
The leaves are typically a dark green color, with a round shape and wavy texture. During warmer seasons, the trees have white flowers that are "densely clustered with five petals" and have a "strong, unpleasant aroma, often likened to rotting fish," ODNR states.
In the fall, the leaves turn from green to maroon, and the tree produces small, hard brown pears that are often eaten by birds. The trees also have "large egg-shaped" buds that are covered in light brown, woolly hairs and stout, reddish-brown twigs.
Callery pear trees were often planted in "disturbed sites" and can be found around commercial spaces, residential properties, roadways and old fields.
The Callery pear tree is considered a significant threat to native land and wildlife. As Paul Cappiello, executive director at Yew Dell Botanical Gardens, writes, Callery pear trees are "weak-wooded, poorly branched, and their flowers smell like a high school locker room laundry pile."
Due to their resilience and the different cultivars' ability to cross-pollinate, a University of Cincinnati biologist found in 2019 that the trees were crowding out and eliminating native plants, wreaking havoc on the ecosystem.
The seeds of these plants are easily dispersed by birds when consumed. As the trees spread, they tend to crowd out native tree species, causing millions of dollars of ecological damage annually, Cappiello added.
Additionally, as the Ohio Department of Natural Resources notes, the Callery pear tree that helped spawn Bradford pears isn't just invasive, it can be dangerous as its fast-growing limbs produce weak wood that often breaks in storms and heavy winds.
Yes, as of January 2023, it is illegal to plant, grow and sell this tree in Ohio due to its invasive nature. Ohioans are encouraged to get rid of them if they're found.
The trees make for a pretty sight while cruising down a neighborhood street or strolling through the park, but they also produce a pretty bad smell.
Callery pear and Bradford pear trees are considered malodorous, according to the Spruce, a home and garden site. The foul odor that drifts from the trees' white or pink flowers is used to attract pollinators.
The unpleasant smell lingers until the white flowers fall off, per the Knoxville News Sentinel.
Local tree services can help remove Callery pears from your yard. Once the tree is cut down, it's important to treat the stump, which might include grinding it down, digging it up or treating it with an herbicide, Greenville News reports.
It's best to remove the tree early in the season before it starts producing berries.
USA TODAY network contributed to this report.
This article originally appeared on Cincinnati Enquirer: Bradford pear trees are pretty but smell awful. Here's why