Once the Callery Pear Tree was Landscapers’ Favorite — Now States Are Banning this Invasive Species and Urging Homeowners to Cut it Down

Ryan W. McEwan • March 28, 2023

When people think of spring, they often picture flowers and trees blooming. And if you live in the U.S. Northeast, Midwest or South, you have probably seen a medium-sized tree with long branches, covered with small white blooms – the Callery pear ( Pyrus calleryana ).

For decades, Callery pear – which comes in many varieties, including “Bradford” pear, “Aristocrat” and “Cleveland Select” – was among the most popular trees in the U.S. for ornamental plantings. Today, however, it’s widely recognized as an invasive species. Land managers and plant ecologists like me are working to eradicate it to preserve biodiversity in natural habitats.

As of 2023, it is illegal to sell, plant or grow Callery pear in Ohio. Similar bans will take effect in South Carolina and Pennsylvania in 2024. North Carolina and Missouri will give residents free native trees if they cut down Callery pear trees on their property.

How did this tree, once in high demand, become designated by the U.S. Forest Service as “ Weed of the Week ”? The devil is in the biological details.

A Kentucky extension specialist explains why Callery pears initially seemed like a solution, but have proved to be a major problem.

A quasi-perfect tree

Botanists brought the Callery pear to the U.S. from Asia in the early 1900s. They intentionally bred the horticultural variety to enhance its ornamental qualities. In doing so, they created an arboricultural wunderkind. As The New York Times observed in 1964 :

“Few trees possess every desired attribute, but the Bradford ornamental pear comes unusually to close to the ideal.”

Modern varieties of Callery pear produce an explosion of white flowers in springtime, followed by deep green summer foliage that turns deep red and maroon in autumn. They also are very tolerant of urban soils, which can be highly compacted and hard for roots to penetrate. The trees grow quickly and have a rounded shape, which made them suitable for planting in rows along driveways and roadsides.

Tree with leaves mostly shaded red.
A Callery pear turning red in fall. Ryan McEwan , CC BY-ND

During the post-World War II suburban development boom, Callery pear trees became extremely popular in residential settings. In 2005 the Society of Municipal Arborists named the “Chanticleer” variety the urban street tree of the year. But the breeding process that created this and other varieties of Callery pear was producing unexpected results.

Cloning to produce an American original

To ensure that each Callery pear tree had bright blooms, red foliage and other desired traits, horticulturists created identical clones through a process known as grafting : creating seedlings from cuttings of trees with the desired characteristics.

Grafting is a method for propagating new fruit trees using buds from existing trees and fusing them onto a branch or stem of another tree, which is called the rootstock.

This approach eliminated the messy complexity of mixing genes during sexual reproduction and ensured that when each tree matured, it would have the characteristics that homeowners desire. Every tree of a specific variety was a genetically identical clone.

Grafting also meant Callery pear trees could not make fruits. Some fruit trees, such as peaches and tart cherries, can fertilize their flowers with their own pollen. In contrast, Callery pear is self-incompatible: pollen on an individual tree cannot fertilize flowers on that tree. And since all Callery pears of a specific variety planted in a neighborhood would be identical clones, they would effectively be the same tree.

If a tree can’t produce fruits, it can’t disperse into natural habitats. Gardeners and landscapers thought it was perfectly safe to plant Callery pear near natural habitats, such as prairies, because the species was trapped in place by its reproductive biology. But the tree would break free from its isolation and spread seeds far and wide.

The great escape

University of Cincinnati botanist Theresa Culley and colleagues have found that as horticulturalists tinkered with Callery pears to produce new versions, they made the individuals different enough to escape the fertilization barrier. If a neighborhood had only “Bradford” pear trees, then no fruits could be produced – but once someone added an “Aristocrat” pear to their yard, then these two varieties could fertilize each other and produce fruits.

When Callery pear trees in gardens and parks started depositing seeds in nearby areas, wild populations of the trees became established. Those wild trees could pollinate one another, as well as neighborhood trees.

In today’s landscape, Callery pear is astonishingly fertile. The prolific flowering that horticulturists intentionally bred into these varieties now yields tremendous crops of pears each year. Although these little pears are generally not edible by humans, birds feed on the fruit, then fly away and excrete the seeds into natural habitats. Callery pear has become one of the most problematic invasive species in the eastern United States.

A thorny problem

Like other invasives, Callery pears crowd out native species. Once Callery pear seedlings spread from habitat edges into grasslands , they have advantages that allow them to dominate the site.

In my research lab , we have found that Callery pear leafs out very early in spring and drops its leaves late in fall. This enables it to soak up more sun than native species. We also have discovered that during invasion, these trees alter the soil and release chemicals that suppress the germination of native plants.

Callery pear is highly resistant to natural disturbances. In fact, when my graduate student Meg Maloney tried to kill the trees by using prescribed fires or applying liquid nitrogen directly to stumps after cutting the trees down, her efforts failed. Instead, the trees sprouted aggressively and seemingly gained strength.

Once Callery pear has escaped into natural areas, its seedlings produce very sharp, stiff thorns that can puncture shoes or even tires. This makes the trees a menace to people working in the area, as well as to native plants. Another nuisance factor is that when Callery pears bloom, they produce a strong odor that many people find unpleasant.

Currently, directly applying herbicides is the only known control for a Callery pear invasion. But the trees are so successful at spreading that poisoning their seedlings may simply create space for other Callery pear seedlings to establish. It is unclear how habitat managers can escape a confounding ecological cycle of invasion, herbicide application and re-invasion.

An open space studded with Callery pear trees, with dead grasses between the trees.
A Callery pear invasion is crowding out native species on this agricultural land, converting it to woodland. Oklahoma State University Extension , CC BY-ND

Banned but not gone

In response to work by the Ohio Invasive Plants Council and other experts, Ohio has taken the extraordinary step of banning Callery pear to thwart its ecological invasion into natural habitats. But the trees are common in residential areas across the state and have established vigorous populations in natural habitats. Ecologists will be working well into the future to maintain openness and biodiversity in areas where Callery pear is invading.

In the meantime, homeowners can help. Horticulturists recommend that people who have a Callery pear on their property should remove it and replace it with something that is not an invasive species. Few trees possess every desired attribute, but many native trees have visually attractive features and will not threaten ecosystems in your region.The Conversation

Ryan W. McEwan , Professor of Biology, University of Dayton

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Common Sense for the Eastern Shore

By John Christie March 3, 2026
Just up the road from Maryland’s Eastern Shore lies Independence National Historical Park in Philadelphia. Administered by the National Park Service (NPS), the park is dedicated to the preservation of historical structures and properties associated with the American Revolution and the founding and growth of the United States. The centerpiece of the park is Independence Hall, where the Declaration of Independence and the United States Constitution were debated and adopted by America's Founding Fathers in the late 18th century. Nearby is the Liberty Bell, an iconic symbol of American independence, displayed in the Liberty Bell Center. In the park as well is what’s called the President’s House, an exhibit on the site of the first official residence of the president of the United States. President Washington occupied the Philadelphia President's House from 1790 to 1797. His successor, John Adams, lived there from 1797 to 1800. Although the original structure no longer exists, the exhibit includes a view of the foundation of the house where our first two presidents lived with their families. Research has turned up information about nine enslaved Africans owned by Washington and brought to Philadelphia’s presidential residence during his time there. To commemorate the lives of those slaves, their names are etched in a wall in the exhibit: Oney Judge, Austin, Christopher Sheels, Giles, Hercules Posey, Joe Richardson, Moll, Paris, and Richmond. The site includes exhibits on how their struggles for freedom represented this country’s progress away from the horrors of slavery and into an era where the founding ideals of “Life, Liberty and the pursuit of Happiness” could be achieved for every American. An intended theme of the President’s House exhibit is “Liberty: The Promises and Paradoxes.” “The promises of liberty and equality granted in the founding documents present a paradox: not only were they ideals to strive for but they were unfulfilled promises for people who struggled to be fully included as citizens of our nation.” ------------------------------------------------------------ On March 27, 2025, President Trump signed Executive Order 14253, “Restoring Truth and Sanity to American History.” EO14253 stated in part: “Over the past decade, Americans have witnessed a concerted and widespread effort to rewrite our nation's history, replacing objective facts with a distorted narrative driven by ideology rather than truth.” In order to “restore truth in American history,” EO14253 directed the Secretary of the Interior to ensure that all public monuments, memorials, or similar properties within the Department of the Interior's jurisdiction do not contain descriptions or other content that “inappropriately disparage” Americans past or living (including persons living in colonial times) and instead focus on the greatness of the achievements and progress of the American people. In response to this order, on January 22, 2026, the NPS suddenly removed 34 educational panels and video exhibits that referenced slavery and provided information about the individuals enslaved at the President’s House. The day these exhibits were removed, the City of Philadelphia filed a lawsuit in the federal district court in Philadelphia against Secretary of the Interior Doug Burgum, the Department of the Interior, Acting Director of NPS Jessica Bowron, and the NPS itself, claiming that the removal of the displays was unlawful agency action. On February 16, Judge Cynthia Rufe ordered the Trump administration to restore the slavery-related exhibits at the national park site, holding that NPS lacked the power “to dissemble and disassemble historical truths.” In court, the government asserted it alone had the power to erase, alter, remove, and hide historical accounts on taxpayer and local government-funded monuments within its control. According to Judge Rufe, to claim that “truth is no longer self-evident, but rather the property of the elected chief magistrate and his appointees and delegees, at his whim to be scraped clean, hidden, or overwritten” comes right out of George Orwell’s 1984. In her opinion, no government agency can “arbitrarily” decide what is true, “based on its own whims or the whims of the new leadership.” “It is not disputed that President Washington owned slaves.” Moreover, Judge Rufe determined the removed displays were not mere decorations to be taken down and redisplayed; rather, they were a memorial to the “men, women, and children of African descent who lived, worked, and died as enslaved people in the United States of America.” Each person who visits the President’s House and does not learn of the realities of founding-era slavery receives a false account of this country’s history. Removal of the crucial interpretive materials strips the site of that truth and deprives the public of educational opportunities designed to be free and accessible. For Judge Rufe, the abrupt elimination of historically significant educational material is like “pulling pages out of a history book with a razor.” John Christie was for many years a senior partner in a large Washington, D.C. law firm. He specialized in anti-trust litigation and developed a keen interest in the U.S. Supreme Court about which he lectures and writes.
By CSES Staff March 3, 2026
Last month, Megan Outten, candidate for Wicomico County Council District 7, was endorsed by Run for Something (RFS), a national organization that recruits and supports the next generation of progressive leaders for state and local office. The organization’s slate of newly endorsed candidates includes young, diverse progressives from across the country who are ready to lead in their communities. Outten said, “This campaign has always been powered by our community. By parents, teachers, small business owners, and neighbors who know we can do better. Run for Something’s endorsement affirms what we already know here in Wicomico: when everyday people step up to lead, we change what’s possible. Together, we’re building the kind of local government that plans ahead, listens first, and puts families at the center of every decision.” “Bold leaders like Megan are at the forefront of the fight for our rights and freedoms at a time when they have never faced greater threats,” said Amanda Litman, Co-Founder and President of Run for Something. “Run for Something is proud to endorse Megan Outten as part of our latest class of young leaders working to secure lasting change in their communities.” Outten’s platform is rooted in real data and shaped by direct community engagement. With Wicomico now the fastest-growing school system on Maryland’s Eastern Shore, and 85% of students relying on additional resources, she points to the county’s lagging investment as a key area for action. “Strong schools lead to strong jobs, thriving industries, and healthier communities,” Outten said. “Our schools and infrastructure are at a tipping point. We need leadership that stops reacting after things break — and starts investing before they do.” About Run for Something: Amanda Litman and Ross Morales Rocketto launched RFS in January 2017 with a simple premise: to help young, diverse progressives run for state and local offices in order to build a bench for the future. RFS aims to lower the barriers to entry for these candidates by helping them with organization building, connecting them with a robust community, and providing access to the trainings they need to be successful. Since its founding, RFS has helped elect over 1,600 candidates across the country — including 43 candidates in red-to-blue seats in the 2025 election cycle. Today, RFS has the largest database of any Democratic organization, with nearly 80,000 people reaching out since November 2024 with interest in running for office. In total, over 250,000 young people from across the country have signed up to run and gained access to RFS’s resources since the organization launched — a powerful signal that a new generation is showing up to lead.
By Liam Bowman, Capital News Service March 3, 2026
The Trump administration is still arresting immigrants in D.C. without warrants or probable cause despite a judge’s previous ruling that the practice was unlawful, a coalition of immigrant rights groups alleges in a recent court filing. A federal judge ruled in December that the administration’s use of warrantless immigration arrests likely violated federal law and issued a preliminary injunction prohibiting such arrests without probable cause. The ruling was in response to a lawsuit filed by immigrant rights groups and four migrants who were arrested without warrants last year during President Donald Trump’s law enforcement surge in the capital. But federal immigration officials in D.C. are failing to comply with that order, continuing to make warrantless arrests “without the required probable cause determinations,” according to the Feb. 19 motion by plaintiffs. The lawsuit alleges immigration authorities began operating under an “arrest first, ask questions later” policy to comply with arrest quotas imposed after Trump took office last year — and started to ignore the probable cause requirements under immigration law. Click here to read the rest of the article , on the Capital News Service website. The article also details the arrest stories of the plaintiffs who were tricked, and concerns about D.C. police cooperation with immigration authorities. Capital News Service is a student-powered news organization run by the University of Maryland Philip Merrill College of Journalism. For 26 years, they have provided deeply reported, award-winning coverage of issues of import to Marylanders.
By John Christie February 17, 2026
These are the words from Emma Lazarus’ famous 1883 sonnet “The New Colossus” inscribed on a bronze plaque on the pedestal of the Statue of Liberty. In 1990, Congress reaffirmed this vision of America by establishing the Temporary Protected Status program. TPS is designed to provide humanitarian relief to foreign nationals in the United States who come from disaster-stricken countries. In its present form, the TPS legislation gives the Secretary of the Department of Homeland Security responsibility for the program. However, the legislation prescribes the kind of country conditions severe enough to warrant a designation under the statute, the specific time frame for any such designation, and the process for periodic review of a TPS designation which could culminate in termination or extension. All initial TPS designations last from six to eighteen months. Before the expiration of a designation, the statute mandates that the Secretary shall review the conditions in the foreign state to decide if the conditions for the designation continue to be met, following consultation with appropriate agencies of the government. Extension is the default; the designation “shall be extended” unless the secretary affirmatively determines that conditions are “no longer met.” ------------------------------------------------------------- A massive earthquake devastated Haiti in January 2010, and precipitated an unprecedented humanitarian crisis. Shortly after, then-DHS Secretary Janet Napolitano, after consultation with the State Department, designated Haiti for TPS due to “extraordinary conditions.” Haitian nationals in the United States continuously as of January 12, 2010, could thus apply for TPS, and obtained the right to remain and work in the U.S. while Haiti maintained its TPS designation. Napolitano set the initial TPS designation for 18 months. As Haiti’s deterioration worsened, successive DHS secretaries have extended this program. Gang violence and kidnappings have spiked. In 2021, a group of assailants killed Haiti’s then-President Jovenel Moïse. In 2023, another catastrophic earthquake hit Haiti. In 2024, in response to these conditions, then-DHS Secretary Alejandro Mayorkas once again extended and redesignated Haiti for TPS, this time effective through February 3, 2026. During the 2024 election cycle, the GOP candidate, Donald Trump clearly indicated that time had not tempered his views on Haiti, characterized by him as a “shithole country” during his first term. He stated that when elected, he would “absolutely revoke” Haiti’s TPS designation and send “them back to their country.” On December 1, 2025, Kristi Noem, DHS secretary in the second Trump administration, announced, “I just met with the president. I am recommending a full travel ban on every damn country that’s been flooding our nation with killers, leeches, and entitlement junkies. Our forefathers built this nation on blood, sweat, and the unyielding love of freedom, not for foreign invaders to slaughter our heroes, suck dry our hard-earned tax dollars, or snatch the benefits owned to Americans. We don’t want them, not one.” So says the official responsible for overseeing the TPS program. And one of those (her word) “damn” countries is Haiti. Three days before making the above post, Secretary Noem announced she would terminate Haiti’s TPS designation as of February 3, 2026. Five Haitian TPS holders filed suit in federal court in Washington initially seeking an injunction against the termination of the Haitian TPS program pending the completion of the litigation. These plaintiff TPS holders are not “killers, leeches, or entitlement junkies.” They are instead a neuroscientist researching Alzheimer’s disease, a software engineer at a national bank, a laboratory assistant in a toxicology department, a college economics major, and a full-time registered nurse. The case was assigned to district court judge Ana Reyes who granted the plaintiffs’ injunction request on February 2, 2026, by way of an 83-page opinion. The plaintiffs charge that Secretary Noem preordained her termination decision because of hostility to non-white immigrants. According to Judge Reyes, “This seems substantially likely. Secretary Noem has terminated every TPS country designation to have reached her desk — twelve countries up, twelve countries down.” Judge Reyes also decided that Noem’s conclusion that Haiti (a majority non-white country) faces only “merely concerning” conditions cannot be squared with the “perfect storm” of “suffering and staggering” humanitarian toll described in page after page of the record in the case. In Judge Reyes’ view, Noem also ignored Congress’s requirement that she review the conditions in Haiti “after consulting with appropriate agencies.” Indeed, the record indicates she did not consult other agencies at all. Her “national interest” analysis focuses on Haitians outside the United States or here illegally, ignoring that Haitian TPS holders already live here and legally so. And though Noem states that the analysis must include “economic considerations,” Judge Reyes concluded Noem ignored altogether the billions that Haitian TPS holders contribute to the economy. The administration’s primary response in the litigation has been to assert that the TPS statute gives Secretary Noem “unbounded” discretion to make whatever determination she wants, any way she wants. Yes, Judge Reyes acknowledges, the statute does grant Noem some discretion. But, in Judge Reyes’ opinion, “not unbounded discretion.” To the contrary, Congress passed the TPS statute to standardize the then ad hoc temporary protection system; in Judge Reyes’ words, "to replace executive whim with statutory predictability.” The administration also argued that the harms to Haitian TPS holders were “speculative” if they are forced to return to Haiti. Because the State Department presently warns, “Do not travel to Haiti for any reason,” the administration asserts that harm is “speculative” only because DHS “might not” remove them. However, according to Judge Reyes, this argument fails to take Secretary Noem at her word: “We don’t want them. Not one.” The public interest also favors the injunction, in the opinion of Judge Reyes. Secretary Noem complains of the strains that unlawful immigrants place on our immigration-enforcement system. Noem’s answer is to turn 352,959 lawful TPS Haitian immigrants into unlawful immigrants overnight. Noem complains of strains to our economy; her answer is to turn employed lawful immigrants who contribute billions in taxes into the legally unemployable. Noem complains of strains to our health care system. Noem’s answer is to turn the insured into the uninsured. “This approach is many things – but the public interest is not one of them,” according to Judge Reyes. The opinion of Judge Reyes concludes: “Kristi Noem has a First Amendment right to call immigrants killers, leeches, entitlement junkies, and any other inapt name she wants. Secretary Noem, however, is constrained by both our Constitution and the law to apply faithfully the facts to the law in implementing the TPS program. The record to-date shows she has yet to do that. The administration has already appealed. John Christie was for many years a senior partner in a large Washington, D.C. law firm. He specialized in anti-trust litigation and developed a keen interest in the U.S. Supreme Court about which he lectures and writes.
By Office of the Governor February 16, 2026
Gov. Wes Moore signed legislation on February 17, 2026, to prohibit State and local jurisdictions from deputizing officers for federal civil immigration enforcement activity. The law, created under SB 245/HB 444 , is effective immediately. “In Maryland, we defend Constitutional rights and Constitutional policing — and we will not allow untrained, unqualified, and unaccountable ICE agents to deputize our law enforcement officers,” Moore said. “This bill draws a clear line: we will continue to work with federal partners to hold violent offenders accountable, but we refuse to blur the lines between state and federal authority in ways that undermine the trust between law enforcement and the communities they serve. Maryland is a community of immigrants, and that's one of our greatest strengths because this country is incomplete without each and every one of us.” “As an immigrant, this bill is deeply personal to me,” said Lt. Gov. Aruna Miller. “Immigrants make Maryland stronger every day, and our communities are safer when everyone feels protected and valued. This legislation ensures that our law enforcement resources remain focused on keeping Marylanders safe, not on actions that create fear in our neighborhoods. I thank the bill sponsors and Governor Moore for their leadership in ensuring Maryland remains a place where dignity and opportunity go hand in hand.” U.S. Department of Homeland Security Immigration and Customs Enforcement, also known as ICE, established its 287(g) program to authorize local law enforcement officials to perform federal civil immigration enforcement functions under ICE’s oversight. Under SB 245/HB 444, State and local jurisdictions in Maryland are prohibited from engaging in such agreements. Any local jurisdictions with standing 287(g) agreements must terminate them immediately. The legislation does not: Authorize the release of criminals Impact State policies and practices in response to immigration detainers that are issued by the U.S. Department of Homeland Security Prevent the State or local jurisdictions from continuing to work with the federal government on shared public safety priorities, including the removal of violent criminals who pose a risk to public safety Prevent State or local jurisdictions from continuing to notify ICE about the impending release of an individual of interest from custody or from coordinating the safe transfer of custody within constitutional limits State and local law enforcement will also maintain the ability to work with the federal government on criminal investigations and joint task forces unrelated to civil immigration enforcement. Any individual who is charged with a crime is entitled to due process and, if convicted, must serve their sentence.
By Sarah Boden and Drew Hawkins, Gulf States Newsroom February 16, 2026
And now, the enhanced Affordable Care Act subsidies that many Americans, including farmers, relied on to purchase health insurance are gone, having expired at the end of December.
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