Callery Pear, Bradford Pear (Pyrus calleryana)

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Rosanae
Order	Rosales
Family	Rosaceae
Genus	Pyrus

Scientific Name

Pyrus calleryana

Common Name

Callery pear (Bradford pear)

Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.

Plant

Deciduous tree to 60 feet (18 m) in height and boles 2 feet (0.6 m) in diameter, widely planted as an ornamental tree due to its uniform teardrop crown shape, early spring cover of white blossoms, and brilliant orange-to-red fall foliage. Leaves ovate and long-petioled, alternate and tufted on stubby thorned or nonthorned branchlets. Abundant (rarely few) small pears in fall and winter spread by birds and other animals, with varying seed fertility. Several commercial sterile varieties can cross-pollinate with certain other pear species in close proximity to produce fertile hybrids. Also, fertile varieties are commonly used as a rootstock for grafting most pear species and can dominate after grafted crowns are damaged. Major branches fork from trunk at narrow angles, often splitting at the juncture after wind and ice storms.

Stem

Twigs initially hairy, stubby, and tipped by a sharp thorn in escaped plants, being longer branched with few thorns in cultured, planted varieties. Terminal and lateral bud scales loose, gray-hairy and elongated to 0.5 inch (1.2 cm). Twigs reddish brown to gray with scattered or many light dots (lenticels) that elongate with age to form horizontal light lines on branches and boles. Bark of trunk increasingly vertically fissured, becoming cross-checked with age. Stems and boles often dappled with gray and green lichens.

Leaves

Alternate, often tufted on short branchlets. Initially circular and hairy, maturing to glossy and ovate or slightly cordate with a tapering tip, 1.5 to 3.5 inches (4 to 9 cm) long and wide, leathery with finely crenate and wavy margins sometimes having a pronounced tip. Dark green above and light green below, becoming brilliantly red, yellow, to maroon in fall. Thin petioles 1 to 2 inches (2.5 to 5 cm) long with thin stipules that shed early.

Flowers

March to May. Large clusters of brilliantly white, 5-petaled flowers, 1 inch (2.5 cm) across with many jutting, maroon-tipped anthers, appearing before leaves, tufted often from midthorn, covering trees to make conspicuous invaders in early spring. Emit an unpleasant odor and can cause allergic sinus reactions.

Fruit and seeds

June to February. Persistent clusters of small pears (pomes), 0.3 to 0.5 inch (8 to 12 mm) long and wide, green ripening to tan then maroon with numerous surface speckles, dangling on thin, 1-inch (2.5 cm) long stems. Fleshy, tart but edible, containing 2 to 6 maroon seeds and numerous stone cells.

Ecology

Rapid growing, forms thickets and dense stands by root sprouts. Tolerates partial shade and a variety of soils from wet to droughty. Hybridizes with other callery pear varieties and Asian pear (P. betulifolia Bunge). Pollinated by insects. Fertility and fruit production vary widely, but close colonies result in more viable fruit. Fruiting starting at 3 years. Spreads by prolific bird- and animal-dispersed seeds. Seeds require 60 to 90 days of cold to germinate, which can occur in the fruit. Widely invading over a large range due to cultivars that have been bred for cold hardiness.

Resembles

Resembles leaves of both common pear (Pyrus spp.) that has larger fruit and Chinese tallowtree [Triadica sebifera (L.) Small] that has dangling spring flowers and clusters of white fruit in fall and winter. Also resembles flowers of another invasive, common pearlbush [Exochorda racemosa (Lindl.) Rehder] that blooms in early spring with similar bright white flowers that occur in racemes and leaves are elliptic and serrated above the middle.

History and use

Native to China, Korea, and Taiwan, the original “Bradford” cultivar was introduced into Maryland in 1908 for breeding resistance to fire blight disease into fruiting pears, although not successful. Since the 1950s about 20 ornamental cultivars have been developed and are still widely sold and planted. All capable of producing viable seeds.

Distribution

Found as single trees and some dense infestations throughout the region.

Callery pear or Bradford pear (Pyrus calleryana Decne.) is a widely planted deciduous tree to 60 feet (18 m) in height and with boles to 2 feet (0.6 m) in diameter. Major branches fork from trunk at narrow angles, and often split at the juncture after wind and ice storms. Leaves are ovate and long petioled, alternate, turn red in fall, and tufted on stubby thorned or nonthorned branchlets. Abundant small pears are typically present in fall and winter and are spread by birds and possibly other animals. Seed viability varies by location, and several commercial sterile varieties can crosspollinate with certain other pear species in close proximity to produce fertile hybrids. Thickets and dense stands are formed by root sprouts. This species can tolerate partial shade and a variety of soils. Fruiting starts at 3 years.

Management strategies

• Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of fruit in a dumpster or burn.
• Treat when new plants are young to prevent seed formation.
• Cut and bulldoze when fruit are not present.
• Manual pulling and tree wrenching is hindered by thorny branches and eye protection should be used.
• Manually pull new seedlings and tree wrench saplings when soil is moist, ensuring removal of all roots.
• Burning treatments are suspected of having minimal topkill effect due to scant litter.
• Treatment combinations should be used that are appropriate for dense thickets with limited access. Access trails may need to be cut.

Recommended control procedures

Trees. For stems too tall for foliar sprays, cut large stems and immediately treat the stump tops with Garlon 3A or a glyphosate herbicide as a 25- to 50-percent solution (2 to 6 quarts per 3-gallon mix). ORTHO Brush-B-Gon, Enforcer Brush Killer, and Vine-X are effective undiluted for treating cut-stumps and available in retail garden stores (safe to surrounding plants). Make stem injections using undiluted Garlon 3A during June through September in cut-spacings as specified on the herbicide label. A subsequent foliar application may be required to control new seedlings and resprouts.

Saplings. Apply Garlon 4 as a 20-percent solution (5 pints per 3-gallon mix) in a labeled basal oil product, vegetable oil or mineral oil with a penetrant, or fuel oil or diesel fuel (where permitted); or apply undiluted Pathfinder II to young bark as a basal spray. Basal spray applications can be made year-round.

Seedlings. Thoroughly wet all leaves with one of the following herbicides in water with a surfactant: a glyphosate herbicide or Garlon 3A as a 2-percent solution (8 ounces per 3-gallon mix), Arsenal AC* as a 0.25-percent solution (1 ounce per 3-gallon mix), or Arsenal PowerLine* as a 0.5-percent solution (2 ounces per 3-gallon mix).

* Nontarget plants may be killed or injured by root uptake.

Images

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