Callery Pear
Encyclopedia
The Callery pear is a species of pear native to China
and Vietnam
, in the rose family (Rosaceae
). Callery pears are deciduous
tree
s growing to 15 to 20 m (49.2 to 65.6 ft) tall, often with a conic to rounded crown. Their leaves
are oval, 4 to 7 cm (1.6 to 2.8 in) long, glossy dark green above, and slightly paler below. The white, five-petal
ed flower
s are about 2 to 3 cm (0.78740157480315 to 1.2 in) in diameter. They are produced abundantly in early spring, before the leaves expand fully. The flowers have an unpleasant odor.
The fruit
s of the Callery pear are small (less than one cm in diameter), and hard (almost woody) until softened by frost
, after which they are readily taken by bird
s, which disperse the seed
s in their droppings. In summer, the 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. Sometimes, several of these fall colors may be present on an individual leaf. However, since the color often develops very late in fall, the leaves may be killed by a hard frost before full color can develop.
Callery pears are remarkably resistant to sicknesses or blight
; they are more often killed by storms or high winds than by sickness. Some cultivars, such as 'Bradford', are particularly susceptible to storm damage.
The species is named after the Italian-French sinologue
Joseph-Marie Callery (1810–1862) who sent specimens of the tree to Europe from China.
In much of North America
, cultivar
s of Callery pear are so widely planted as ornamental trees that they have become a ubiquity in many urban and suburban communities. It is tolerant of a variety of soil types, drainage levels and soil acidity. Its crown shape varies from ovate to elliptical. The symmetry
of several cultivar
s lends to their use in somewhat formal settings, such as city streets, shopping centers, office parks, and industrial park
s. Its dense clusters of white blossom
s are conspicuous in early spring along the boulevards of many eastern U.S.
towns. At the latitude of Pittsburgh, Pennsylvania
, the trees often remain green until mid-November, and in warm autumns, the colors are often a brilliant end to the fall color season, 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.
Several cultivars of Callery pear are offered commercially, including 'Aristocrat', 'Autumn Blaze', 'Bradford' (the commonly planted Bradford pear), 'Capital', 'Cleveland Select', 'New Bradford', 'Redspire', and 'Whitehouse'.
The neat, dense upward growth of 'Bradford' — which made it desirable in cramped urban
spaces — also results in a multitude of narrow, weak forks, unless corrected by selective pruning
at an early stage. These weak crotches make the Bradford Pear very susceptible to storm
damage where snow
fall is heavy or when ice storm
s occur, or during the high wind
s of severe thunderstorm
s. Because of this, and the resulting relatively short life span
(typically less than 25 years), many groups have discouraged further planting
of 'Bradford' itself in favor of other, stronger Callery pear cultivars (such other as 'Cleveland Select'), as well as increased use of locally native ornamental tree species.
(of any species) has one of the finest textures of the fruitwoods. It is prized for making woodwind instruments, and pear veneer is used in fine furniture.
Callery pear has been used as rootstock
for grafting
such pear cultivar
s as Comice, Bosc
, or Seckel, and especially for nashi pear
. Pyrus calleryana was first introduced into the United States (in 1909 and 1916) for agricultural experimentation
, pre-dating the recognition of the potential value appreciation of the species as an ornamental plant in the 1950s.
in many areas of eastern North America, outcompeting many native plants and trees. In the northeastern United States, wild Callery pears sometimes form extensive, nearly pure stands in old fields, along roadsides, and in similar disturbed areas.
While various cultivars of the Callery pear are commonly planted for their ornamental values, their prolifically produced fruits are taken by bird
s, 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.
Callery pear is reported as established outside cultivation in 152 counties in 25 states in the United States. 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.
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
, in the rose family (Rosaceae
Rosaceae
Rosaceae are a medium-sized family of flowering plants, including about 2830 species in 95 genera. The name is derived from the type genus Rosa. Among the largest genera are Alchemilla , Sorbus , Crataegus , Cotoneaster , and Rubus...
). Callery pears are deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s growing to 15 to 20 m (49.2 to 65.6 ft) tall, often with a conic to rounded crown. Their leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are oval, 4 to 7 cm (1.6 to 2.8 in) long, glossy dark green above, and slightly paler below. The white, five-petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
ed flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are about 2 to 3 cm (0.78740157480315 to 1.2 in) in diameter. They are produced abundantly in early spring, before the leaves expand fully. The flowers have an unpleasant odor.
The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s of the Callery pear are small (less than one cm in diameter), and hard (almost woody) until softened by frost
Frost
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
, after which they are readily taken by bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, which disperse the seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s in their droppings. In summer, the 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. Sometimes, several of these fall colors may be present on an individual leaf. However, since the color often develops very late in fall, the leaves may be killed by a hard frost before full color can develop.
Callery pears are remarkably resistant to sicknesses or blight
Blight
Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. It is simply a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this...
; they are more often killed by storms or high winds than by sickness. Some cultivars, such as 'Bradford', are particularly susceptible to storm damage.
The species is named after the Italian-French sinologue
Sinology
Sinology in general use is the study of China and things related to China, but, especially in the American academic context, refers more strictly to the study of classical language and literature, and the philological approach...
Joseph-Marie Callery (1810–1862) who sent specimens of the tree to Europe from China.
Cultivation
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s of Callery pear are so widely planted as ornamental trees that they have become a ubiquity in many urban and suburban communities. It is tolerant of a variety of soil types, drainage levels and soil acidity. Its crown shape varies from ovate to elliptical. The symmetry
Symmetry
Symmetry generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically pleasing proportionality and balance; such that it reflects beauty or perfection...
of several cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s lends to their use in somewhat formal settings, such as city streets, shopping centers, office parks, and industrial park
Industrial park
An industrial park is an area zoned and planned for the purpose of industrial development...
s. Its dense clusters of white blossom
Blossom
In botany, blossom is a term given to the flowers of stone fruit trees and of some other plants with a similar appearance that flower profusely for a period of time in spring...
s are conspicuous in early spring along the boulevards of many eastern U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
towns. At the latitude of Pittsburgh, Pennsylvania
Pittsburgh, Pennsylvania
Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...
, the trees often remain green until mid-November, and in warm autumns, the colors are often a brilliant end to the fall color season, although in a cold year they may get frozen off before coloring. In the South
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...
, Callery pears tend to be among the more reliable coloring trees.
Several cultivars of Callery pear are offered commercially, including 'Aristocrat', 'Autumn Blaze', 'Bradford' (the commonly planted Bradford pear), 'Capital', 'Cleveland Select', 'New Bradford', 'Redspire', and 'Whitehouse'.
The neat, dense upward growth of 'Bradford' — which made it desirable in cramped urban
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
spaces — also results in a multitude of narrow, weak forks, unless corrected by selective pruning
Pruning
Pruning is a horticultural practice involving the selective removal of parts of a plant, such as branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping , improving or maintaining health, reducing risk from falling branches, preparing nursery specimens for...
at an early stage. These weak crotches make the Bradford Pear very susceptible to storm
Storm
A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather...
damage where snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
fall is heavy or when ice storm
Ice storm
An ice storm is a type of winter storm characterized by freezing rain, also known as a glaze event or in some parts of the United States as a silver thaw. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least of ice on exposed surfaces...
s occur, or during the high wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
s of severe thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s. Because of this, and the resulting relatively short life span
Life expectancy
Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...
(typically less than 25 years), many groups have discouraged further planting
Landscaping
Landscaping refers to any activity that modifies the visible features of an area of land, including:# living elements, such as flora or fauna; or what is commonly referred to as gardening, the art and craft of growing plants with a goal of creating a beautiful environment within the landscape.#...
of 'Bradford' itself in favor of other, stronger Callery pear cultivars (such other as 'Cleveland Select'), as well as increased use of locally native ornamental tree species.
Uses
Pear woodWood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
(of any species) has one of the finest textures of the fruitwoods. It is prized for making woodwind instruments, and pear veneer is used in fine furniture.
Callery pear has been used as rootstock
Rootstock
A rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...
for grafting
Grafting
Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...
such pear cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s as Comice, Bosc
Bosc
Bosc may refer to a type of pear, the Bosc pear.Bosc may also be used as a surname:* Thomas Bosc, a rugby league player.* Louis Augustin Guillaume Bosc, a French botanist....
, or Seckel, and especially for nashi pear
Nashi Pear
Pyrus pyrifolia is a pear tree species native to China, Japan, and Korea. The tree's edible fruit is known by many names, including: Asian pear, Chinese pear, Korean pear, Japanese pear, Taiwan pear, and sand pear.....
. Pyrus calleryana was first introduced into the United States (in 1909 and 1916) for agricultural experimentation
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, pre-dating the recognition of the potential value appreciation of the species as an ornamental plant in the 1950s.
Invasiveness
The Callery pear is an invasive speciesInvasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in many areas of eastern North America, outcompeting many native plants and trees. In the northeastern United States, wild Callery pears sometimes form extensive, nearly pure stands in old fields, along roadsides, and in similar disturbed areas.
While various cultivars of the Callery pear are commonly planted for their ornamental values, their prolifically produced fruits are taken by bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, which disperse the seeds
SEEDS
SEEDS is a voluntary organisation registered under the Societies Act of India....
in their droppings. The various cultivars are generally themselves self-incompatible
Self-incompatibility in plants
Self-incompatibility is a general name for several genetic mechanisms in angiosperms, which prevent self-fertilization and thus encourage outcrossing...
, unable to produce fertile seeds when self-pollinated
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
, or cross-pollinated with another tree of the same cultivar. However, if different cultivars of Callery pears are grown in proximity (within insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
-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
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
, 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.
Callery pear is reported as established outside cultivation in 152 counties in 25 states in the United States. 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.