No pear tree for that partridge? Ohio will ban most a year from now

Dec. 11—Those long braids of dainty white flowers, the glossy heart-shaped leaves, the symmetrical, pyramidal appearance — we have grown to cherish our pear trees.

They line our streets, wrap our cul de sacs, and stand proudly in their showcase role as the ornamental star of the show in suburban front yard landscapes.

But the ubiquitous Bradford pear is not the charming adornment we have coveted and made the cheerful default choice for our parks and gardens. It is yet another wolf in sheep's clothing, an invasive plant that lost its allure once its genetic deception and prolific nature were illuminated by scientific light.

"It is the Jekyll and Hyde in your yard," said Zack Edwards, owner of Black Diamond Garden Center on Tremainsville Road. "It's a good-looking tree that's tough and can handle a lot of environments and doesn't have a lot of issues with pests, but the negative impact is they also produce a lot of volunteers so they've been pretty much uncontrollable in some areas."

Ohio has banned the sale and planting of the trees, effective in January of 2023 when we'll see the end of a five-year grandfathering period intended to give tree growers and landscapers time to deplete their stock.

That ban will also strongly affirm the coming end of a more than 50-year love affair with this non-native tree that arrived from Asia with the best of intentions. It was pretty, it was free of insect problems and resistant to fireblight, a bacterial disease that had decimated orchards of European pear trees in the United States.

The Bradford pear and other ornamentals were developed from the Chinese Callery pear as botanists sought to access its favorable genes. The Bradford was believed to be a thornless, fruit-less ornamental variety whose flowers were unable to pollinate themselves.

Once other hybrid versions of the Callery pear were produced and released, these pear trees began to cross-pollinate with the Bradfords already on the landscape, and the resulting trees were able to form fruit and viable seeds. The spread and proliferation of these volunteers could not be controlled as the problems with these pear trees revealed themselves.

As Teresa Culley, professor and head of the Department of Biological Sciences at the University of Cincinnati, revealed in her 2007 research that started to peel back the cover of these ornamental pear trees, nature hornswoggled us once we messed with the pear tree's hereditary cache.

After these other varieties crossed with Bradford pear trees already on the landscape, birds ate the small fruits that had sprouted on these trees and carried the seeds far from the parent tree, spreading this spawn across the countryside. Culley pointed out that the highly-identifiable springtime explosion of the white flowers of rogue pear trees had been found along highways and country roads, abandoned fields, and in nature reserves and wetlands.

David Coyle, forest health and invasive species specialist in the Department of Forestry and Environmental Conservation at Clemson University, is a leading voice in South Carolina's move to follow Ohio's lead and outlaw the pear trees, which will take effect in that state in 2024. The ban includes Bradford pear trees and any other pear varieties propagated from the most commonly used rootstock.

Pear trees are not native to North America — the D'Anjou, Bartlett, and Bosc varieties we buy in the store came from Europe. Coyle explained that when the European pear varieties got hit hard with the blight decades ago, it opened the door to America for different species that might provide some genetic protection against the disease. A horticulturalist in Maryland who worked with the new arrivals named one variation Bradford in honor of his former boss.

With Bradfords in widespread use as cross-pollinating with other pear varieties, the resulting trees often grew in clusters, squeezing out native plants.

"They were noticed escaping cultivation back in the mid-sixties, but at that time the economic benefit was too large. That took over the thought process in the eighties and nineties, and these things were planted all over the place," Coyle said. "When I first came to South Carolina in 1999, these trees were not in the wild, but when I came back at the end of 2020, they were everywhere."

Joe Boggs, an assistant professor with the Ohio State University Extension who works with the OSU. Department of Entomology, said that while the early Bradfords did not bear fruit, once fruits started to show up on the trees this was treated as an oddity. "We didn't recognize the fruits were a sinister portent of things to come," Boggs wrote.

After traversing Ohio's highways in the spring of 2020, Boggs made the gloomy conclusion that "the genie is truly out of the bottle.

"Escaped trees are simply too widespread and too well established for Callery pears to be wiped away, particularly with the continued infusion of new seed from the many housing developments, parks, towns, and cities where the pears represent a significant portion of tree plantings," Boggs said.

While its beauty when flush with flowers and its often attractive shape are not areas of contention, the Bradford hybrid has displayed some prominent flaws. Its "steep V-crotch" structure makes its branches prone to snap in high winds, and the odor when flowered has been compared to the smell of rotting fish, that of a wet dog, and worse.

"Besides the weak structure that causes excessive snapping of the branches, since these trees are insect resistant there are no bugs for birds to feed on," Coyle said.

As the pear tree ban looms just a year away in Ohio, homeowners, landscapers, and nursery managers are searching for alternatives in the folder of native plants. Dan Kenny, Chief of Plant Health with the Ohio Department of Agriculture, said there will be no roundup of existing trees, just encouragement to take the native route.

"Our regulations are not going to come after the pear tree in someone's yard, and there are a lot of them out there," Kenny said. "The law is in place to basically stop the flow. We hope to see folks have a plan to replace these trees with something not on the invasive list."

First Published December 11, 2021, 1:30pm