Pyrus calleryana

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Pyrus calleryana
Pyrus calleryana.JPG
Pyrus calleryana callery pear blossom.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Rosaceae
Genus: Pyrus
Species:
P. calleryana
Binomial name
Pyrus calleryana
Synonyms [1]
List
    • Pyrus dimorphophyllaMakino
    • Pyrus kawakamiiHayata
    • Pyrus maireiH.Lév.

Pyrus calleryana, also known as the Callery pear or Bradford pear, is a species of pear tree native to China and Vietnam, [2] in the family Rosaceae. It is most commonly known for its cultivar 'Bradford' and its offensive odor, widely planted throughout the United States and increasingly regarded as an invasive species. [2]

Contents

Pyrus calleryana is deciduous, growing to 5 to 8 m (16 to 26 ft) tall, [3] often with a conical to rounded crown. The leaves are oval, 4 to 8 cm (1+1⁄2 to 3 in) long, glossy dark green above and pale beneath. They have long petioles alternately arranged on branches. [4] The white, five-petaled flowers are about 2 to 2.5 cm (3⁄4 to 1 in) 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 1 centimetre (3⁄8 in) 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.

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. [5] [6]

Cultivation

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'.[ citation needed ]

In the United States

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. [7] [8] 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." [9]

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. [10] [11] [12] [13] Individuals tend to flower young, exhibit quick growth, and create seeds that are dispersed primarily through birds. [14] According to extension specialist Kelly Oten of North Carolina State University, the smell attracts flies which are the primary pollinators rather than bees. [15] At the latitude of Pittsburgh, Pennsylvania, the trees often remain green until mid-November,[ citation needed ] 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.[ citation needed ]

Subtaxa

The following varieties are currently accepted: [1]

As an invasive species

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. [2] 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. [16]

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), [2] 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.[ citation needed ]

Callery pear is reported as established outside cultivation in 152 counties in 25 states in the United States. [17] 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. [2] 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. [18]

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. [19]

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. [20]

In 2023, the state of Ohio banned the sale and cultivation of Callery pear trees. [21]

Uses

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. [22] Pear wood is also among those preferred for preparing woodcuts for printing, either end-grained for small works or side-grained for larger. [23]

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. [2]

Related Research Articles

<span class="mw-page-title-main">Pear</span> Edible fruits from the genus Pyrus

Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus Pyrus, in the family Rosaceae, bearing the pomaceous fruit of the same name. Several species of pears are valued for their edible fruit and juices, while others are cultivated as trees.

<i>Malus</i> Flowering genus, rose family Rosaceae

Malus is a genus of about 32–57 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples and wild apples.

<i>Rosa multiflora</i> Species of flowering plant in the rose family Rosaceae

Rosa multiflora is a species of rose known commonly as multiflora rose, baby rose, Japanese rose, many-flowered rose, seven-sisters rose, Eijitsu rose and rambler rose. It is native to eastern Asia, in China, Japan, and Korea. It should not be confused with Rosa rugosa, which is also known as "Japanese rose", or with polyantha roses which are garden cultivars derived from hybrids of R. multiflora. It was introduced to North America, where it is regarded as an invasive species.

<i>Pyrus pyrifolia</i> Species of pear with round crisp grainy fruit

Pyrus pyrifolia is a species of pear tree native to southern China and northern Indochina that has been introduced to Korea, Japan and other parts of the world. The tree's edible fruit is known by many names, including Asian pear, Persian pear, Japanese pear, Chinese pear, Korean pear, Taiwanese pear, apple pear, zodiac pear, three-halves pear, papple, naspati and sand pear. Along with cultivars of P. × bretschneideri and Pyrus ussuriensis, the fruit is also called the nashi pear. Cultivars derived from Pyrus pyrifolia are grown throughout East Asia, and in other countries such Pakistan, Nepal, Australia, New Zealand, and America. Traditionally in East Asia the tree's flowers are a popular symbol of early spring, and it is a common sight in gardens and the countryside.

<i>Koelreuteria paniculata</i> Species of flowering plant

Koelreuteria paniculata is a species of flowering plant in the family Sapindaceae, native to China. Naturalized in Korea and Japan since at least the 1200s, it was introduced in Europe in 1747, and to America in 1763, and has become a popular landscape tree worldwide. Common names include goldenrain tree, pride of India, China tree, and the varnish tree.

<i>Cercidiphyllum</i> Genus of trees

Cercidiphyllum is a genus containing two species of plants, both commonly called katsura. They are the sole members of the monotypic family Cercidiphyllaceae. The genus is native to Japan and China and unrelated to Cercis (redbuds).

<i>Magnolia tripetala</i> Species of tree

Magnolia tripetala, commonly called umbrella magnolia or simply umbrella-tree, is a deciduous tree native to the eastern United States in the Appalachian Mountains, the Ozarks, and the Ouachita Mountains. The name "umbrella tree" derives from the fact that the large leaves are clustered at the tips of the branches forming an umbrella-shaped structure.

<i>Prunus cerasifera</i> Species of plum

Prunus cerasifera is a species of plum known by the common names cherry plum and myrobalan plum. It is native to Southeast Europe and Western Asia, and is naturalised in the British Isles and scattered locations in North America. Also naturalized in parts of SE Australia where it is considered to be a mildly invasive weed of bushland near urban centers. P. cerasifera is believed to one of the parents of the cultivated plum, Prunus domestica perhaps crossing with the sloe, Prunus spinosa, or perhaps the sole parent. This would make it a parent of most of the commercial varieties of plum in the UK and mainland Europe - Victoria, greengages, bullace etc.

<i>Pyrus communis</i> Species of pear tree

Pyrus communis, the common pear, is a species of pear native to central and eastern Europe, and western Asia.

<i>Albizia julibrissin</i> Species of plant

Albizia julibrissin, the Persian silk tree, pink silk tree, or mimosa tree, is a species of tree in the Fabaceae family, native to southwestern and eastern Asia.

Ulmus bergmannianaC.K.Schneid., commonly known as Bergmann's elm, is a deciduous tree found across much of China in forests at elevations of 1500–3000 m.

<i>Gymnosporangium sabinae</i> Species of fungus

Gymnosporangium sabinae is a species of rust fungus in the subdivision Pucciniomycotina. Known as pear rust, European pear rust, or pear trellis rust, it is a heteroecious plant pathogen with Juniperus sabina as the main primary (telial) host and Pyrus communis as the main secondary (aecial) host.

<i>Pyrus pyraster</i> Species of tree

Pyrus pyraster, also called European wild pear, is a species of pear of the family Rosaceae.

<span class="mw-page-title-main">Stepanavan Dendropark</span> Arboretum in Armenia

Officially Sochut Dendropark named after Edmund Leonowicz, commonly knowns as Stepanavan Dendropark, is an arboretum located near the Gyulagarak village, Lori Province, Armenia. Located around 85 km (53 mi) north of the capital Yerevan, the park was founded in 1931 by Polish engineer-forester Edmund Leonowicz. The arboretum is 35 ha in total of which 17.5 ha consist of natural forest and 15 ha of ornamental trees.

<span class="mw-page-title-main">Frank Nicholas Meyer</span> American botanist

Frank Nicholas Meyer was a United States Department of Agriculture explorer who travelled to Asia to collect new plant species. The Meyer lemon was named in his honor.

<i>Prunus avium</i> Species of flowering plant in the rose family Rosaceae

Prunus avium, commonly called wild cherry, sweet cherry or gean is a species of cherry, a flowering plant in the rose family, Rosaceae. It is native to Europe, Anatolia, Maghreb, and Western Asia, from the British Isles south to Morocco and Tunisia, north to the Trondheimsfjord region in Norway and east to the Caucasus and northern Iran, with a small isolated population in the western Himalaya. The species is widely cultivated in other regions and has become naturalized in North America, New Zealand and Australia.

<i>Pyrus bourgaeana</i> Species of pear tree

Pyrus bourgaeana, the Iberian pear, is a close relative of Pyrus communis L. The latter was domesticated about 2500 years ago. This small tree is widely distributed across the southern Iberian Peninsula and northern Morocco, where it coexists with four Pyrus species: P. communis L., P. cordata Dew., P. spinosa Forssk, and P. nivalis Jacq. Characteristics to discriminate these species are the width of fruit peduncle, petal size, leaf width and petiole length served to the taxa.

<i>Pyrus cordata</i> Species of pear tree

Pyrus cordata, the Heart-leaved pear or Plymouth pear, is a rare wild species of pear belonging to the family Rosaceae. It gets its name in Spanish, Portuguese and French from the shape of its leaves. In the UK, it is known as Plymouth Pear after the city of Plymouth in Devon, where it was originally found in 1870 The Plymouth pear was one of the British trees to be funded under English Natures Species Recovery Programme.

<i>Pyrus syriaca</i> Species of plant in the family Rosaceae

Pyrus syriaca is a deciduous tree in the Rosaceae family. It is referred to by the common name Syrian pear. It is the only pear species which grows in the wild in Lebanon, Turkey, Syria, Israel, and Palestine.

<i>Pyrus ussuriensis</i> Species of pear tree

Pyrus ussuriensis, also known as the Ussurian pear, Harbin pear, and Manchurian pear, is a species of flowering plant in the family Rosaceae.

References

  1. 1 2 "Pyrus calleryana Decne". Plants of the World Online. Board of Trustees of the Royal Botanic Gardens, Kew. 2017. Retrieved 22 September 2020.
  2. 1 2 3 4 5 6 Swearingen, J.; B. Slattery; K. Reshetiloff & S. Zwicker (2010). Plant Invaders of Mid-Atlantic Natural Areas (4th ed.). Washington, D.C.: National Park Service and U.S. Fish and Wildlife Service. p. 168.
  3. ↑ Gu, Cuizhi; Spongberg, Stephen A. "Pyrus calleryana". Flora of China. Vol. 9 – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  4. ↑ "Callery pear (Bradford pear), Pyrus calleryana Rosales: Rosaceae". www.invasive.org. Retrieved 2023-10-23.
  5. ↑ Reimer, F.C., "A promising new pear stock," The Monthly Bulletin, California State Commission of Horticulture, 5:5 (May 1916), p. 167.
  6. ↑ Bretschneider, Emil (1898), History of European botanical discoveries in China, vol. 1, Sampson Low, p. 525, ISBN   9783863471651
  7. ↑ Popkin, Gabriel (2016-03-18). "Opinion | The Ups and Downs of the Bradford Pear". The New York Times. ISSN   0362-4331 . Retrieved 2019-03-23.
  8. ↑ "The Curse of the Bradford Pear: What you should know about the trees and their problems". The Greenville News. Retrieved 2019-03-23.
  9. ↑ "BRADFORD PEAR HAS MANY ASSETS; New Ornamental Fruit Offers Sturdy Form and Early Bloom". The New York Times. 1964-01-05. ISSN   0362-4331 . Retrieved 2019-03-23.
  10. ↑ Pyrus calleryana at Floridata
  11. ↑ Reid, Liz (24 April 2015). "What's That Smell? The Beautiful Tree That's Causing Quite a Stink" (Web publication). National Public Radio. Core Publisher. Retrieved 23 November 2019.
  12. ↑ Morgans, Julian (October 18, 2017). "Here's Why the Trees on Your Street Smell Like Semen". Vice.
  13. ↑ Spector, Dina (April 26, 2013). "Why All Of New York City Smells Like Sex". Business Insider Australia.
  14. ↑ Culley, Theresa M.; Hardiman, Nicole A. (2007-12-01). "The Beginning of a New Invasive Plant: A History of the Ornamental Callery Pear in the United States". BioScience. 57 (11): 956–964. doi:10.1641/b571108. ISSN   1525-3244.
  15. ↑ Cataudella, Kimberly (March 12, 2022). "'Bounty' offered on invasive Bradford pear trees in NC". News and Observer .
  16. ↑ Culley, Theresa M. (2017). "The Rise and Fall of the Ornamental Callery Pear Tree". Arnold. 74 (3): 8.
  17. ↑ Vincent, M.A. (2005). "On the spread and current distribution of Pyrus calleryana in the United States". Castanea. 70 (9): 20–31. doi:10.2179/0008-7475(2005)070[0020:OTSACD]2.0.CO;2. PMC   4103147 . PMID   25202586.
  18. ↑ Culley, Theresa M. (2017). "The Rise and Fall of the Ornamental Callery Pear Tree". Arnold. 74 (3): 10.
  19. ↑ Lawson, Nancy. "Plant This, Not That! Choose native plants to help put your garden to work for wildlife". The Humane Society of the United States. Retrieved 17 Jan 2016.
  20. ↑ Nebhut, Andrea N.; Dukes, Jeffrey S. (December 2023). "Invasion by Callery pear (Pyrus calleryana) does not affect understory abundance or diversity in early-successional meadows". Invasive Plant Science and Management. 16 (4): 215–224. doi:10.1017/inp.2023.28. ISSN   1939-7291.
  21. ↑ McEwan, Ryan W. (8 March 2023). "Once the Callery pear tree was landscapers' favorite – now states are banning this invasive species and urging homeowners to cut it down". TheConversation . Retrieved 10 March 2023.
  22. ↑ Ohio State University Pyrus calleryana Archived 2012-02-22 at the Wayback Machine
  23. ↑ Escher, M.C. The Graphic Work of M. C. Escher. Pub: Oldbourne Book Co. London. 1961. page 9
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