Pyrus calleryana

Pyrus calleryana is deciduous, growing to {{convert|5|to|8|m|ft|abbr=on|0}} tall,{{eFloras|2|200011181|Pyrus calleryana |last1=Gu |first1=Cuizhi |first2=Stephen A. |last2=Spongberg |volume=9}} often with a conical to rounded crown. The leaves are oval, {{convert|4|to|8|cm|in|abbr=on|frac=2}} long, glossy dark green above and pale beneath. They have long petioles alternately arranged on branches.{{Cite web |title=Callery pear (Bradford pear), Pyrus calleryana Rosales: Rosaceae |url=https://www.invasive.org/browse/subinfo.cfm?sub=10957#:~:text=The%20leaves%20are%20alternate,%20simple,with%20wavy,%20slightly%20toothed%20margins.&text=Flowering%20occurs%20early%20in%20the,The%20flowers%20are%201%20in. |access-date=2023-10-23 |website=www.invasive.org}} The white, five-petaled flowers are about {{convert|2|to|2.5|cm|in|abbr=on|frac=8}} in diameter. They are produced abundantly in early spring, before the leaves expand fully.

The fruits (which are often assumed to be inedible due to their abundant, cyanide laced seeds) of the Callery pear are small (less than {{convert|1|cm|frac=8}} in diameter), and hard, almost woody, until softened by frost, after which they are readily taken by birds, which disperse the seeds in their droppings. In summer, the shining foliage is dark green and very smooth, and in autumn the leaves commonly turn brilliant colors, ranging from yellow and orange to more commonly red, pink, purple, and bronze. However, since the color often develops very late in autumn, the leaves may be killed by a hard frost before full color can develop.

Callery pears are remarkably resistant to disease or fireblight. However, some cultivars, such as 'Bradford', are particularly susceptible to storm damage and are regularly disfigured or killed by strong winds, winter weather, or limb loss due to their naturally rapid growth rate and acute vertical branching.

It was described by Joseph Decaisne in 1871.

The following varieties are currently accepted:

• Pyrus calleryana var. calleryana – China, Japan, and Vietnam, introduced to the United States and Iraq
• Pyrus calleryana var. fauriei {{small|(C.K.Schneid.) Rehder}} – Korea
• Pyrus calleryana var. integrifolia {{small|T.T.Yu}} – China
• Pyrus calleryana var. koehnei {{small|(C.K.Schneid.) T.T.Yu}} – China
• Pyrus calleryana var. lanceata {{small|Rehder}} – China

The species is named after the Italian-French missionary Joseph-Marie Callery (1810–1862), a sinologue who sent specimens of the tree to Europe from China.Reimer, F.C., "A promising new pear stock," The Monthly Bulletin, California State Commission of Horticulture, 5:5 (May 1916), p. 167.{{citation |author=Bretschneider, Emil |title=History of European botanical discoveries in China |publisher=Sampson Low |year=1898 |volume=1 |page=525 |isbn=9783863471651 |url=https://books.google.com/books?id=FFU-g42KVEIC}}

It is native to China, Japan, Korea, Taiwan, and Vietnam.

Numerous cultivars of Callery pear are offered commercially, including 'Aristocrat', 'Autumn Blaze', 'Bradford', 'Capital', 'Chanticleer' (also known as 'Cleveland Select'), 'New Bradford', 'Redspire', and 'Whitehouse'.{{cn|date=December 2023}}

File:Bradford 9288.JPG|alt=Cultivated Callery pears in flower

File:2014-11-02 14 11 35 Bradford Pear during autumn along Hunters Ridge Drive in Hopewell Township, New Jersey.jpg|Autumn color

File:2014-11-02 12 22 20 Bradford Pear foliage during autumn along Scotch Road in Ewing, New Jersey.JPG|Autumn color

The trees were introduced to the U.S. by the United States Department of Agriculture facility at Glenn Dale, Maryland, as ornamental landscape trees in the mid-1960s. They became popular with landscapers because they were inexpensive, transported well and grew quickly. Lady Bird Johnson promoted the tree in 1966 by planting one in downtown Washington, D.C.{{Cite news|url=https://www.nytimes.com/2016/03/19/opinion/the-ups-and-downs-of-the-bradford-pear.html|title=Opinion {{!}} The Ups and Downs of the Bradford Pear|last=Popkin|first=Gabriel|date=2016-03-18|work=The New York Times|access-date=2019-03-23|language=en-US|issn=0362-4331}}{{Cite web|url=https://www.greenvilleonline.com/story/news/2019/02/27/curse-bradford-pear-trees-what-you-should-know/2994154002/|title=The Curse of the Bradford Pear: What you should know about the trees and their problems|website=The Greenville News|language=en|access-date=2019-03-23}} The New York Times also promoted the tree saying, "Few trees possess every desired attribute, but the Bradford ornamental pear comes unusually close to the ideal."{{Cite news|url=https://www.nytimes.com/1964/01/05/archives/bradford-pear-has-many-assets-new-ornamental-fruit-offers-sturdy.html|title=BRADFORD PEAR HAS MANY ASSETS; New Ornamental Fruit Offers Sturdy Form and Early Bloom|date=1964-01-05|work=The New York Times|access-date=2019-03-23|language=en-US|issn=0362-4331}}

In much of North America these cultivars, particularly 'Bradford', are widely planted as ornamental trees. The trees are tolerant of a variety of soil types, drainage levels, and soil acidity. Their crown shape varies from ovate to elliptical, but may become asymmetric from limb loss due to excessive and unstable growth rate. The initial symmetry of several cultivars leads to their attempted use in settings such as industrial parks, streets, shopping centers, and office parks. Their dense clusters of white blossoms are conspicuous in early spring, with an odor often compared to rotting fish or semen.[https://floridata.com/Plants/Rosaceae/Pyrus+calleryana/233 Pyrus calleryana at Floridata]{{cite news |last1=Reid |first1=Liz |title=What's That Smell? The Beautiful Tree That's Causing Quite a Stink |url=https://www.npr.org/2015/04/24/401943000/whats-that-smell-the-beautiful-tree-thats-causing-quite-a-stink |access-date=23 November 2019 |work=National Public Radio |publisher=Core Publisher |date=24 April 2015 |ref=NPR |language=English |format=Web publication}}{{cite web |url=https://www.vice.com/en/article/7x4zza/heres-why-the-trees-on-your-street-smell-like-semen |title=Here's Why the Trees on Your Street Smell Like Semen |date=October 18, 2017 |first=Julian |last=Morgans |work=Vice}}{{cite web |url=https://www.businessinsider.com/bradford-pear-tree-semen-sex-smell-2013-4 |title=Why All Of New York City Smells Like Sex |date=April 26, 2013 |first=Dina |last=Spector |work=Business Insider Australia}} Individuals tend to flower young, exhibit quick growth, and create seeds that are dispersed primarily through birds.{{Cite journal |last1=Culley |first1=Theresa M. |last2=Hardiman |first2=Nicole A. |date=2007-12-01 |title=The Beginning of a New Invasive Plant: A History of the Ornamental Callery Pear in the United States |url=https://doi.org/10.1641/B571108 |journal=BioScience |volume=57 |issue=11 |pages=956–964 |doi=10.1641/b571108 |issn=1525-3244}} According to extension specialist Kelly Oten of North Carolina State University, the smell attracts flies which are the primary pollinators rather than bees.{{cite news|url=https://www.newsobserver.com/news/state/north-carolina/article259306539.html|title='Bounty' offered on invasive Bradford pear trees in NC|last=Cataudella|first=Kimberly|work=News and Observer|date=March 12, 2022}} At the latitude of Pittsburgh, Pennsylvania, the trees often remain green until mid-November,{{citation needed|date=May 2018}} and in warm autumns, the colors are often bright, although in a cold year they may get frozen off before coloring. In the South, Callery pears tend to be among the more reliable coloring trees.{{cn|date=December 2023}}

A famous example of a Callery pear is the one that was found to have survived the destruction of the Twin Towers on 9/11 and was restored to full health subsequently. It is often referred to as "the Survivor Tree".

The Bradford pear and related cultivars of Pyrus calleryana are regarded as invasive species in many areas of the Eastern and Midwestern regions in North America, outcompeting many native plants and trees. In the northeastern United States, wild Callery pears sometimes form extensive, nearly homogeneous stands in old fields, along roadsides, and in similar disturbed areas. The species was first noticed spreading outside of human cultivation in the 1990s, and by the latter half of the 2000s, Callery pear trees were widespread and could be found in habitats ranging from wetlands to forests.{{cite journal |last1=Culley |first1=Theresa M. |title=The Rise and Fall of the Ornamental Callery Pear Tree |journal=Arnold |date=2017 |volume=74 |issue=3 |page=8}}

While various cultivars of the Callery pear are commonly planted for their ornamental value, their prolifically produced fruits are taken by birds, which disperse the seeds in their droppings. The various cultivars are generally themselves self-incompatible, unable to produce fertile seeds when self-pollinated, or cross-pollinated with another tree of the same cultivar. However, if different cultivars of Callery pears are grown in proximity (within insect-pollination distance, about 300 ft or 100 m), they often produce fertile seeds that can sprout and establish wherever they are dispersed. The resulting wild individuals, of various genetic backgrounds, can in turn interbreed, producing more viable seed and furthering expansion and dispersal of the wild stand of the species. These plants often differ from the selected cultivars in their irregular crown shape and (sometimes) presence of thorns.{{cn|date=December 2023}}

Callery pear is reported as established outside cultivation in 152 counties in 25 states in the United States.{{cite journal | author = Vincent, M.A. | title = On the spread and current distribution of Pyrus calleryana in the United States | journal = Castanea | volume = 70 | pages = 20–31 | doi = 10.2179/0008-7475(2005)070[0020:OTSACD]2.0.CO;2 | year = 2005 | issue = 9 | pmc = 4103147 | pmid=25202586}}{{Obsolete source|reason=This source is from 2005, a newer source should be added because it has likely expanded its range since then|date=January 2025}} While these wild plants are sometimes called "Bradford pear" (for the 'Bradford' cultivar), they are actually wild-growing descendants of multiple genotypes of Pyrus calleryana, and hence more correctly referred to by the common (or scientific) name of the species itself. Currently, the spread of the invasive trees is limited by their intolerance to extreme cold, but they are creeping northward as climate change causes warming temperatures, and have been found as far north as Madison, Wisconsin.{{cite journal |last1=Culley |first1=Theresa M. |title=The Rise and Fall of the Ornamental Callery Pear Tree |journal=Arnold |date=2017 |volume=74 |issue=3 |page=10}}

The Bradford pear in particular has become further regarded as a nuisance tree for its initially neat, dense upward growth, which made it desirable in cramped urban spaces. Without corrective selective pruning at an early stage, these weak crotches result in a multitude of narrow, weak forks that are very susceptible to storm damage. Because of this, and the resulting relatively short life span (typically less than 25 years), many groups have discouraged further planting of 'Bradford' and other similarly structurally deficient Callery pear cultivars (such as 'Cleveland Select') in favor of increasing use of locally native ornamental tree species.{{cite web|last=Lawson|first=Nancy|title=Plant This, Not That! Choose native plants to help put your garden to work for wildlife|url=http://www.humanesociety.org/news/magazines/2015/05-06/plant-this-not-that-choose-native-plants-over-exotic-invasives.html|work=The Humane Society of the United States|access-date=17 Jan 2016}}

It should be recognized that even though P. calleryana is considered an invasive species, there have been cases in which it did not have an impact when introduced as a nonnative species. In young, low-density populations, this tree was found to have no significant effect on species richness or diversity in its surrounding environment. to understand how this species interacts in a given environment, further studies should be considered.{{Cite journal |last1=Nebhut |first1=Andrea N. |last2=Dukes |first2=Jeffrey S. |date=December 2023 |title=Invasion by Callery pear (Pyrus calleryana) does not affect understory abundance or diversity in early-successional meadows |url=https://www.cambridge.org/core/journals/invasive-plant-science-and-management/article/invasion-by-pyrus-calleryana-does-not-affect-understory-abundance-or-diversity-in-earlysuccessional-meadows/A94008EE990D6B451ADFE0CE6D799A6E |journal=Invasive Plant Science and Management |language=en |volume=16 |issue=4 |pages=215–224 |doi=10.1017/inp.2023.28 |issn=1939-7291}}

In 2023, the state of Ohio banned the sale and cultivation of Callery pear trees.{{cite web|title=

Once the Callery pear tree was landscapers' favorite – now states are banning this invasive species and urging homeowners to cut it down|last=McEwan|first=Ryan W.|url=https://theconversation.com/once-the-callery-pear-tree-was-landscapers-favorite-now-states-are-banning-this-invasive-species-and-urging-homeowners-to-cut-it-down-198724|website=TheConversation|date=8 March 2023|access-date=10 March 2023}}

File:CalleryPearC.JPG|alt=Fruit

File:Callery Pear Fruit.JPG|In winter|alt=Fruit in winter

Pear wood (of any species) is among the finest-textured of all fruitwoods. It is prized for making woodwind instruments, and pear veneer is used in fine furniture.Ohio State University [http://hcs.osu.edu/plantlist/description/py_ryana.html Pyrus calleryana ] {{webarchive|url=https://web.archive.org/web/20120222024609/http://hcs.osu.edu/plantlist/description/py_ryana.html |date=2012-02-22 }} Pear wood is also among those preferred for preparing woodcuts for printing, either end-grained for small works or side-grained for larger.Escher, M.C. The Graphic Work of M. C. Escher. Pub: Oldbourne Book Co. London. 1961. page 9

Callery pear has been used as rootstock for grafting such pear cultivars as Comice, Bosc, or Seckel, and especially for Nashi. Pyrus calleryana was first introduced into the United States in 1909 and 1916, largely influenced by the dedicated research of Frank N. Meyer, plant explorer for the US Department of Agriculture, commonly known for the discovery of the Meyer lemon, for agricultural experimentation, pre-dating recognition in the 1950s of the species' potential as an ornamental plant.

{{Reflist}}

{{Commons category|Pyrus calleryana}}

• [http://www.nps.gov/plants/alien/pubs/midatlantic/pyca.htm Plant Invaders of Mid-Atlantic Natural Areas]
• [https://web.archive.org/web/20090809164333/http://www.cas.vanderbilt.edu/bioimages/species/frame/pyca80.htm Pyrus calleryana images at bioimages.vanderbilt.edu]
• [http://www.csrees.usda.gov/newsroom/impact/2008/nri/01153_peartree.html "Scientists Look for Clues Into How Tree Populations Become Invasive" Jan 15, 2008 by Stacy Kish, CSREES Staff.]
• {{PFAF|Pyrus calleryana}}
• {{CalPhotos|Pyrus|calleryana}}

{{Pyrus}}

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Category:Naturalized trees of Alabama

Category:Pears

calleryana

Category:Taxa named by Joseph Decaisne