Introduction
Callery pear (Pyrus calleryana) is an Asian species of ornamental pear with more than 20 cultivars planted throughout the Southeast. Popular varieties include Bradford, Chanticleer, Cleveland Select, Autumn Blaze, and Aristocrat. While it was once prized for its spring flowers, oval-shaped canopy, and adaptability to urban environments, it is now evident that Bradford and other varieties of Callery pear exhibit highly invasive traits, such as aggressive proliferation and displacement of native species. Moreover, the tree’s weak branching structure and brittle wood result in frequent breakage, causing post-storm debris and damage to structures, vehicles, and humans. The flowers also emit an unpleasant odor, often described as rotting fish. Callery pear’s invasive nature has drawn growing attention in recent years as the scientific evidence of its invasiveness mounts, states enact legislation to restrict its sale, and grassroots and educational campaigns reach more people.
History of the Bradford Pear and Other Ornamental Varieties in the U.S.
Callery pear was first introduced into the United States in the early 1900s to confer resistance to fire blight (a bacterial disease) in fruit-producing European pear trees (P. communis) (Culley and Hardiman 2007). Soon after, it was discovered that some P. calleryana selections had potential as an ornamental tree and thus, certain varieties were created. The first variety was the Bradford pear (P. calleryana 'Bradford'), developed in the 1950s and prized for its white blossoms in early spring (Figure 1A), bright red foliage in the fall, ability to withstand low-quality soils, and symmetrical oval-shaped canopy (Figure 1B). It is almost entirely pest-free and considered “low maintenance” relative to other horticultural selections. Given its popularity, additional varieties of Callery pear were developed, including Chanticleer, Cleveland Select, Autumn Blaze, and Aristocrat. Because it was the first variety and most widely planted, Bradford pear became a common catch-all name for any of the ornamental varieties. From the 1950s through the 1990s, Callery pears were among the most commonly planted urban trees in the southeastern United States (Figure 2).
Though the trees looked idyllic, many people were quick to notice the pungent odor associated with the flowers, attributed to chemicals emitted to attract pollinators. The smell has been likened to rotting fish and other unsavory odors. Moreover, the tree’s acute branching structure and fast growth lead to weak branch unions. Eventually, the tree can break under its own weight. Mild or moderate storms cause excessive branch and main stem breakage, leaving a mess and, in the worst cases, property damage or personal injury (Figure 3). To make matters worse, within a decade of its introduction, the tree began invading natural areas.
Figure 1. The Bradford pear is a variety of Callery pear that was cultivated, in part, for its showy white flowers (A) that appear in early spring and its symmetrical, oval-shaped canopy (B).
Photos by Kelly Oten, NC State.
Figure 2. Bradford and other varieties of Callery pear are often planted in rows and are known for their ability to thrive in a variety of conditions.
Figure 3. Callery pears are notorious for easily breaking.
Photo by Lauren Gonzalez, NC State.
Wild Callery Pear: The Invasive Offspring
When the Bradford pear was first introduced in the 1950s, it was sterile because it was the lone variety and unable to self-pollinate (Culley and Hardiman 2007). However, as new varieties of Callery pear, like Chanticleer, Cleveland Select, Autumn Blaze, and Aristocrat, were developed and planted, they could cross-pollinate and produce fertile seeds. In addition, Callery pear can sprout new growth from its base; because these trees were developed by combining different rootstock, the sprouts can also cross-pollinate with the flowers on the upper branches. Furthermore, European pear trees (P. communis), the widely planted fruit-producing tree, can also pollinate Callery pear trees.
All varieties of Callery pear can produce viable seed. When birds and other animals eat the fruit and spread the seeds through their droppings, new invasive trees can grow elsewhere. These wild Callery pear trees spread quickly, infiltrating roadsides, agricultural fields, unmanaged lots, urban areas, wetlands, and forests. Such escapes are easy to spot each spring due to their early-blooming white flowers.
Callery pear has had a significant impact on native ecosystems. Its hardiness makes it an adept invader. It has quickly taken over fields and forest edges throughout the eastern United States (Figure 4 and Figure 5). By blooming and producing leaves early in the spring, before most native plants, it shades out and displaces native species. Research indicates that caterpillars prefer Callery pear less than native trees, limiting an essential food source for wildlife like birds (Hartshorn et al. 2022). In addition, Callery pear can form dense thickets, blocking animal movement in wildlife corridors and leaving little to no understory. An understory—made up of smaller trees, shrubs, and plants beneath the canopy—is essential for supporting biodiversity, protecting soil, cycling nutrients, regulating water, and storing carbon.
Wild Callery pear is creating major challenges for land management. Unlike ornamental varieties, the wild offspring have large thorns that can grow up to 4 inches long, which can injure livestock and wildlife (Figure 6). These thorns are even capable of popping tractor tires, posing a hazard to equipment and operators; this is especially problematic on agricultural land and forest plantations, where clearing the land is necessary. To operate safely and efficiently, land managers must either remove Callery pear trees by hand or use costly steel-tracked equipment.
Figure 4. Callery pears are invading various ecosystems, primarily along roadsides and in fields (A, B) but also in forests (C, D).
Photos by Kelly Oten, NC State (A, B), David Coyle, Clemson University (C), and Leslie J. Mehrhoff, University of Connecticut, Bugwood.org (D).
Figure 5. Each spring, Callery pear’s white blooms highlight areas where it has invaded.
Photo by Lauren Gonzalez, NC State.
Figure 6. Wild Callery pear have thorns that can grow up to 4 inches long and puncture tractor tires.
Photo by Kelly Oten, NC State.
Identifying Callery Pear
A small to medium-size tree, Callery pear has showy white flowers in early spring and vibrant red or purple leaves in the fall. Leaves are glossy and oval with serrated edges, and fruits are small and hard. The bark is grayish brown and smooth when young but develops fissures as the tree grows. Callery pear cultivars have a uniform, symmetrical, and dense oval-to-pyramidal shape, one of the characteristics that made them desirable as an ornamental (LeGrand et al. 2025). In contrast, wild Callery pears have a more irregular, sprawling form, often with multiple trunks and uneven branching, giving them a less structured and more naturalized appearance. Wild Callery pears form dense thickets and have large thorns on branches and stems.
Other White-Flowering Spring Trees
Other trees that have white flowers in early spring include black cherry (Prunus serotina), chickasaw plum (P. angustifolia), crabapple (Malus spp.), serviceberry (Amelanchier spp.), and flowering dogwood (Benthamidia florida) (Table 1).
| Species | Flower | Bloom Timing | Bark | Leaf |
|---|---|---|---|---|
| Callery pear (Pyrus calleryana) |
Chuck Bargeron, University of Georgia, Bugwood.org |
February – April |
Chuck Bargeron, University of Georgia, Bugwood.org |
Michasia Dowdy, University of Georgia, Bugwood.org |
| Flowering dogwood (Benthamidia florida) |
Flowering Dogwood Flower Photo Wendy VanDyk Evans, Bugwood.org |
March – April |
Chris Evans, University of Illinois, Bugwood.org |
John Ruter, University of Georgia, Bugwood.org |
| Chickasaw plum (Prunus angustifolia) |
Chris Evans, University of Illinois, Bugwood.org |
March – April |
Karan A. Rawlins, University of Georgia, Bugwood.org |
Karan A. Rawlins, University of Georgia, Bugwood.org |
| Southern crabapple (Malus angustifolia) |
Southern Crabapple Flower Photo John Ruter, University of Georgia, Bugwood.org |
April – May |
John Ruter, University of Georgia, Bugwood.org |
Paul Wray, Iowa State University, Bugwood.org |
| Black cherry (Prunus serotina) |
Paul Wray, Iowa State University, Bugwood.org |
April – May |
Chris Evans, University of Illinois, Bugwood.org |
Chris Evans, University of Illinois, Bugwood.org |
| Blackhaw viburnum (Viburnum prunifolium) |
Blackhaw Viburnum Flower Photo Dow Gardens, Dow Gardens, Bugwood.org |
March – April |
Vern Wilkins, Indiana University, Bugwood.org |
Vern Wilkins, Indiana University, Bugwood.org |
| Downy serviceberry (Amelanchier arborea) |
Downy Serviceberry Flower Photo Paul Wray, Iowa State University, Bugwood.org |
March – May |
John Ruter, University of Georgia, Bugwood.org |
Paul Wray, Iowa State University, Bugwood.org |
| Common pear (Pyrus communis) |
George Chernilevsky, Public domain, Wikimedia Commons |
April |
AnRo0002, CC0, via Wikimedia Commons |
Gil Wojciech, Polish Forest Research Institute, Bugwood.org |
Chickasaw Plum Leaf
Karan A. Rawlins, University of Georgia, Bugwood.org
Callery Pear Flower
Chuck Bargeron, University of Georgia, Bugwood.org
Callery Pear Bark
Chuck Bargeron, University of Georgia, Bugwood.org
Callery Pear Leaves
Michasia Dowdy, University of Georgia, Bugwood.org
Flowering Dogwood Flower
Wendy VanDyk Evans, Bugwood.org
Flowering Dogwood Bark
Chris Evans, University of Illinois, Bugwood.org
Flowering Dogwood Leaves
John Ruter, University of Georgia, Bugwood.org
Chickasaw Plum Flower
Chris Evans, University of Illinois, Bugwood.org
Chickasaw Plum Bark
Chris Evans, University of Illinois, Bugwood.org
Common Pear Leaf
Gil Wojciech, Polish Forest Research Institute, Bugwood.org
Southern Crabapple Flower
John Ruter, University of Georgia, Bugwood.org
Southern Crabapple Bark
John Ruter, University of Georgia, Bugwood.org
Southern Crabapple Leaf
Paul Wray, Iowa State University, Bugwood.org
Black Cherry Flower
Paul Wray, Iowa State University, Bugwood.org
Black Cherry Bark
Chris Evans, University of Illinois, Bugwood.org
Black Cherry Leaf
Chris Evans, University of Illinois, Bugwood.org
Blackhaw Viburnum Flower
Dow Gardens, Dow Gardens, Bugwood.org
Blackhaw Viburnum Bark
Vern Wilkins, Indiana University, Bugwood.org
Blackhaw Viburnum Leaf
Vern Wilkins, Indiana University, Bugwood.org
Downy Serviceberry Flower
Paul Wray, Iowa State University, Bugwood.org
Downy Serviceberry Bark
John Ruter, University of Georgia, Bugwood.org
Downy Serviceberry Leaf
Paul Wray, Iowa State University, Bugwood.org
Common Pear Flower
George Chernilevsky, Public domain, Wikimedia Commons
Common Pear Bark
AnRo0002, CC0, via Wikimedia Commons
Regulations Preventing the Sale and Plantings of Pyrus calleryana
Given the invasive tendency of Callery pears and their negative impacts on native ecosystems, several U.S. states have banned or restricted the sale and planting of the Callery pear. From 2021 to 2024, Ohio, South Carolina, Pennsylvania, and Kansas enacted bans. Localities and municipalities in some states have also implemented bans or restrictions.
Public Awareness and "Bradford Pear Bounties"
Coinciding with legislative actions to prohibit the sale and planting of Callery pear, public awareness of its invasive nature continues to grow. This shift is reflected in expanding media coverage at both local and national levels. In the early 2020s, major pieces in The New York Times, The Washington Post, and USA Today highlighted the issue.
The rising popularity of native plant landscaping and “plant no harm” initiatives has further influenced public perception, reframing invasive species as not just a horticultural concern but a broader environmental responsibility tied to biodiversity conservation. As sustainable gardening and landscaping practices gain traction, support for removing Callery pear has steadily increased.
In response, several states—including North Carolina, South Carolina, Kentucky, and Indiana—have implemented tree replacement programs that incentivize the removal of Callery pears. These initiatives, often referred to as "bounty" programs, typically offer homeowners free native trees in exchange for cutting down Callery pears. The NC Bradford Pear Bounty (Figure 7), a cooperative effort of NC State Extension, North Carolina Urban Forest Council, North Carolina Wildlife Federation, and North Carolina Forest Service, was launched in 2022. Hosted in different locations around the state, the program offers up to five free native trees in exchange for the removal of Callery pears.
Figure 7. Participants in the NC Bradford Pear Bounty pick up complementary native trees in exchange for proof of Callery pear removal on their property.
Photos by Shea Phillips and Kelly Oten, NC State.
What Should You Do with Your Callery Pears?
Landowners with Callery pears on their property are encouraged to remove them and replace them with native trees to reduce continued spread and negative impacts. Fortunately, there are many beneficial trees native to North Carolina that have similar aesthetic value as Callery pear and its many varieties. Examples include flowering dogwood (Benthamidia florida), eastern redbud (Cercis canadensis), serviceberry (Amelanchier spp.), black cherry (Prunus serotina), or Chickasaw plum (Prunus angustifolia).
Removing Callery pear is different in urban areas than in wild landscapes. In urban settings, removal typically involves cutting down the tree and grinding the stump to prevent regrowth. However, because Callery pear can resprout from the roots, applying a targeted herbicide to the freshly cut stump is often necessary for complete eradication. In contrast, controlling wild Callery pear in fields and forest edges is more challenging due to its aggressive spread. Mechanical removal, such as by cutting or bulldozing, may be used, but without follow-up herbicide treatment, new shoots will quickly emerge. The most effective approach in these areas involves a combination of cutting the trees and applying systemic herbicides to stumps and surrounding foliage to prevent regrowth. Regular monitoring and repeated treatments may be necessary to fully eliminate infestations in natural landscapes. Table 2 provides a description of different management methods.
Removal
Wild Callery pear removal can be difficult due to its large thorns and dense growth habits. Smaller plants may be removed by hand, but roots must be removed to prevent resprouting. It is strongly recommended to treat stumps with an appropriate herbicide (for example, glyphosate or triclopyr) after cutting to prevent resprouting. In urban areas, landowners are encouraged to contact a Certified Tree Arborist to ensure safe and effective removal.
Herbicide Application
Many herbicides are recommended to control Callery pear, but only a few are supported by research. For foliar applications, glyphosate (for example, Roundup) and imazapyr consistently provide control (Vogt et al. 2020). Triclopyr (for example, Forestry Garlon XRT) and triclopyr + aminopyralid (for example, Milestone) are effective as basal bark applications, when mixed with a basal oil (Vogt et al. 2020). The hack-and-squirt method is an effective, cost-efficient approach for controlling larger trees, as it delivers herbicide directly into the tree’s vascular system; further, this method minimizes off-target impacts because there is limited contact by herbicides with nearby plants. The hack-and-squirt method involves making incisions (hacks) through the bark and then applying a measured dose of herbicide into each cut. Typically, one hack per 3 inches of trunk diameter is sufficient. According to Russell (2023), best results for hack-and-squirt are exhibited when conducted in the fall and with application rates of 0.5 ml or 1 ml per incision of imazapyr (for example, Polaris AC Complete) or potassium salt of aminocyclopyrachlor (for example, Method 240SL). Note that all of the previous methods will ultimately leave a standing dead tree, which could be a hazard that may require removal. The cut-stump method is highly preferred for larger specimens, as it removes the tree entirely; cut the tree at its base and immediately apply concentrated glyphosate or triclopyr directly to the freshly cut stump. For large trees, herbicide application can be limited to the stump's circumference, as it only needs to penetrate the vascular tissues to be effective (Figure 8). If herbicide is not applied within 5 to 10 minutes, it may not be able to penetrate, and the stump must be recut for the herbicide to be effective.
It is essential to follow all pesticide label instructions, as they are legally binding and enforceable by law.
Monitoring
Callery pear trees are notorious for resprouting; therefore, monitor treated areas regularly for signs of regrowth and reapply treatments if necessary. Always follow local guidelines and regulations when using herbicides and consider consulting with a professional for large-scale infestations or if you are uncertain about the appropriate method.
Figure 8. This cut stump was treated with green-dyed herbicide to ensure coverage of the vascular tissues located beneath the tree bark.
Photo by Kelly Oten, NC State.
Conclusion
Callery pear may have started as a popular ornamental tree, but its invasive nature has become a serious problem for native ecosystems. It is encouraging that more people are becoming aware of harm posed by the Callery pear, with efforts to remove and replace these trees gaining momentum. By choosing native alternatives and supporting removal programs, we can all do our part to protect our land, wildlife, and forests.
Acknowledgments
This work was partly supported by the Extension Capacity Fund (Smith-Lever 3[b] and 3[c], Project Award No. 7007438), from the U.S. Department of Agriculture’s National Institute of Food and Agriculture (USDA NIFA), and by the Renewable Resources Extension Act (RREA), Project Award No. 7009029, from USDA NIFA. Funding for this project was also provided through a USDA Forest Service Urban and Community Forestry Grant from the North Carolina Forest Service, N.C. Department of Agriculture & Consumer Services (NCDA&CS), and the USDA Forest Service. NCDA&CS is an equal opportunity employer.
We also thank the anonymous reviewers who provided comments that improved the quality of this fact sheet.
References
Culley, T. M., and N. A. Hardiman. 2007. "The Beginning of a New Invasive Plant: A History of the Ornamental Callery Pear in the United States." BioScience 57 (11): 956–964. ↲
Hartshorn, J. A., J. F. Palmer, and D. R. Coyle. 2022. "Into the Wild: Evidence for the Enemy Release Hypothesis in the Invasive Callery Pear (Pyrus calleryana) (Rosales: Rosaceae)." Environmental Entomology 51 (1): 216–221. ↲
LeGrand, H., B. Sorrie, and T. Howard. 2025. Vascular Plants of North Carolina [website]. North Carolina Biodiversity Project and North Carolina State Parks. ↲
Russell, D. 2023. Hack and Squirt for Chinese Tallow and Callery Pear Control. PowerPoint Presentation. Auburn University College of Agriculture and Mississippi State University Department of Plant and Soil Sciences. ↲
Vogt, J. T., D. R. Coyle, D. Jenkins, C. Barnes, C. Crowe, S. Horn, C. Bates, and F. A. Roesch. 2020. "Efficacy of Five Herbicide Treatments for Control of Pyrus calleryana." Invasive Plant Science and Management 13 (4): 252–257. ↲
Publication date: July 10, 2025
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