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Pennsylvania begins phasing out sales of Bradford pear tree

By Katherine Mansfield, For The Greene County Messenger 6 min read
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Courtesy of Mason Heberling

Courtesy of Mason Heberling

Leaves from a young Bradford pear tree planted at the carriage entrance to the Carnegie Museum of Natural History were cut and documented by the museumĢƵ herbarium department.

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Each spring, Bradford pear trees add a pop of color to the Carnegie Museum of Natural HistoryĢƵ entrance. Planting of the Callery pear tree was banned inside PittsburghĢƵ city limits in 2015. (Photo courtesy of Mason Heberling)

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Courtey of James H. Miller

Courtey of James H. Miller

Courtey of James H. Miller

Callery pear trees are known for their pretty white blooms.

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Courtesy of David J. Moorhead

Courtesy of David J. Moorhead

Courtesy of David J. Moorhead

Callery pear trees spread like weeds, especially in bright fields, across the commonwealth. Planting of the trees is being phased out because Callery pears choke out native species.

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Katherine Mansfield

Katherine Mansfield

Katherine Mansfield Bradford pear trees line the streets of downtown Washington. The tree was recently added to PennsylvaniaĢƵ Controlled Plants and Noxious Weeds List and will be phased out over the next two years.

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Courtesy of Dr. Ben Dolan

Courtesy of Dr. Ben Dolan

Callery pear trees are often part of public landscaping and, despite a pungent odor when they bloom, are admired for their bright white flowers. These Callery pears line a quiet street in Findlay, Ohio.

The Pennsylvania Department of Agriculture recently announced the addition of Callery pear to its Controlled and Noxious Weed List, along with a plan to phase out the sale and planting of AmericaĢƵ darling by 2024.

“ItĢƵ popular as a street tree. A lot of people line their driveways with them; they are in a lot of public places,” said Scott Weaver, fourth-generation owner of IannettiĢƵ Garden Center in Burgettstown. “It is a very popular tree. It is a very attractive tree. People really like them.”

The public has adored Callery pear trees (also called the Bradford pear tree in Pennsylvania) since the species’ introduction to the United States more than a century ago.

During the early 1960s, the National Arbor Day FoundationĢƵ celebrations included the distribution of the tree nationwide, and as part of Lady Bird JohnsonĢƵ beautification program, she promoted the Callery pear tree.

Callery pear was lauded in the New York Times for its supposed immunity to fire blight, a contagious plant disease. It was easy to grow and its flowers – Dr. Jason Kilgore, associate professor of biology at Washington & Jefferson College, describes them as “showy, white, prolific flowers” – were unmatched in beauty.

The Callery pearĢƵ roots were grafted onto other fruit trees to help them grow; the tree was cloned, and varieties of Callery pear lined the streets of grand cities, including Pittsburgh.

The Callery pear was everywhere.

“Everyone thought it was great,” said Mason Heberling, assistant curator of botany at the Carnegie Museum of Natural History. “ItĢƵ actually quite common. You don’t have to go very far to find it. I’ve seen a lot in old fields, abandoned fields … or cut-down forest along the highway. Callery pear is definitely a concern.”

The Callery pear has been on scientists’ radars for the past couple of decades.

“Most invasive species take time to become invasive,” said Kilgore, who also founded and curates W&JĢƵ campus arboretum. “Callery pear escaped from cultivation where we intended to plant it in the mid-60s, in Maryland. We’ve known since the ’60s that the plant can escape, but the plant didn’t become noticed as an invasive plant until the early ’80s. Since then, the plantĢƵ population exploded across eastern North America.”

And in the last 10 years, said Shannon Powers, press secretary of the DOA, Pennsylvania has taken note of the species’ spread.

“Just over the last decade, itĢƵ become more and more readily apparent itĢƵ naturalizing, itĢƵ spreading,” she said. “ItĢƵ a lovely tree. ItĢƵ beautiful when it blooms, but it smells horrible. For some people, itĢƵ an allergen. That in itself is not reason to ban a sale of a tree. The reason to ban the sale of a tree is when itĢƵ a danger to our environment, our ecology and human health.”

The Callery pear tree and its derivatives, including the Bradford, have begun impacting the growth of native species.

“It spreads without human intervention,” said Heberling. “ItĢƵ not from our area, so itĢƵ competing with our native vegetation and impacting the natural ecological cycle. Other things won’t grow under the Callery pear; thatĢƵ why itĢƵ problematic.”

Another issue with the Callery pear: it supports non-native species, including the European starling, an invasive bird that works with the Callery pear tree, said Kilgore, whose research includes northeastern North American forests. The two species support each other in their spread across the northern part of the continent.

Adding a species to PennsylvaniaĢƵ Controlled Plant and Noxious Weed list is a big deal. Before fall of 2021, just 39 species had made the list, which has been around since 1862.

“ItĢƵ a legal procedure,” said Powers. “ThereĢƵ a deliberation that happens over a period of time. ItĢƵ not just a decision thatĢƵ made and boom, itĢƵ banned. ItĢƵ tied to regulations.”

Before it winds up on the list, a plant is voted on and must be approved by the Controlled Plant and Noxious Weed Committee. The species is published to the stateĢƵ bulletin and, 60 days after publication, it is formally added to the noxious weeds list.

The Callery pear was added in November.

“ItĢƵ very unusual to ban a plant thatĢƵ popularly available in nurseries,” said Powers.

Powers said even more unusual is that the Callery pear tree is not the only species recently added to the noxious weed list.

“A couple months ago, we banned Japanese barberry. ItĢƵ a shrub; itĢƵ very pretty, itĢƵ prolific. But it is thorny, so itĢƵ resistant to deer. It spreads, it harbors ticks, it takes over the understory in the forest,” she said. “It destroys habitat.”

Because both the Bradford pear and Japanese barberry are sold commercially, the state will phase out the two species over the next couple of years “to allow nurseries and landscapers to replace their stock,” Powers said.

The sale ban of Bradford pear trees goes into effect Feb. 9.

In February 2023, the DOA will issue a letter of warning to anyone still selling the Bradford pear tree. The following February, anyone with Callery pear trees remaining in their inventory will be mailed a destruction order.

“ThatĢƵ a big deal,” said Heberling. “It just brings a bit of awareness. That state botanists and state legislatures are saying that this plant is a troubling plant and therefore would encourage people to remove any Callery pears they have – this does make it more in the public consciousness.”

The state already announced exemptions to seedless varieties of Callery pear will be granted, after research confirms those varieties are sterile and won’t pose harm to the environment.

But Heberling and Kilgore agree the best thing for the environment is planting more native species.

“I always encourage people to consider native alternatives: red bud, native dogwood, small trees like blackhaw, wild plum, chokecherry and hawthorn,” said Kilgore. “(Those) give a lot of the similar kinds of vibrant, prolific flowers that we would see in Callery pear, that people like. Not only should they be removing, but they should be replacing with native alternatives.”

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