Pyrus calleryana (Callery Pear)


Michael's Opinion

P. calleryana is a medium sized tree that has become an invasive species in North America. Callery pear seeds were brought from China in the early 1900's and used an under-stock to help combat fireblight in P. communis (Common Pear). The Callery pear is a very hardy tree, Frank Meyer of the USDA in 1918 stated in his journal, "...one finds it growing under all sorts of conditions; one time on dry, sterile mountain slopes; then again with its roots in standing water at the edge of a pond; sometimes in open pine forests...". It has been used in urban areas for its tolerance of full sun and compacted soils. Multiple branches grow from a single stem so included bark and branch breaking is a hazard to watch for. The tree's variant colours of foliage in autumn saw it planted as a desirable street tree but today many cultivars of P. calleryana have replaced it in the landscape.

Botanical Information

FamilyRosaceae
GenusPyrus
Speciescalleryana
CategoryWoody
TypeTree (deciduous)
ReferencesDirr, Michael. Dirr's Encyclopedia of Trees and Shrubs. Portland, Or.: Timber, 2011. Print. Botanica's Pocket Gardening Encyclopedia. Vancouver: Whitecap, 2001. Print.
OriginNative to Hubei Province in China and Central and Southern Korea.
Pronunciation

Details

USDA Hardiness Zone5-8
USDA Hardiness Ref.
Canadian Hardiness Zone6
Canada Hardiness Ref.
RHS Hardiness Ref.
Temperature (°C)-28
Temperature (°F)-18
Height15-20 m
Spread10-13 m
GrowthFast
Flowering PeriodApril, May

Description and Growing Information

General DescriptionOrnamental, fast-growing hardy tree with thorns on the stems at a young age. Odorous flowers producing small, brown, inedible fruit. Leaves are rounded, dark green and glossy.
ID CharacteristicP. calleryana is a medium sized tree with multiple branches often growing in thickets. The fruit is a small brown, rounded pome. It has clusters of 6-12 white flowers producing an unpleasant odour.
ShapeUpright, slightly pyramidal form when young progressing to a narrow rounded crown with horizontal branches towards maturity.
LandscapeIt may be used as an ornamental tree in urban areas and is often seen growing in masses along highways. Now tagged as an invasive species, cultivars of P. calleryana are today commonly used in urban landscapes instead of the species.
PropagationCommonly through seed, although plants are self-incompatible. Cold stratification for 60 days at 4°C is required. Rinse fresh seed with cold water and dry under shade for 48 hours prior to the stratification process. Seeds have a second dormancy if exposed to warm temperatures in late winter.
CultivationTolerant of many soil types including clay and pH levels from 5-7.5. It does best in full-sun and open areas and performs poorly as an understory tree, not surviving where temperatures drop below -28°C.
PestsFireblight and leaf rust are potential problems.
HabitatFound in wetlands, mountain-sides, and open plains in China and Korea. This tree has a low shade tolerance and grows poorly as an understory species and is thus commonly found growing in open areas.
Bark/Stem DescriptionLight brown with a smooth texture when adolescent. Greyish-brown colour and shallow furrows with scaly ridges when mature.
Flower/Leaf Bud DescriptionLarge reddish-brown buds 1.5 cm in length, often tomentose with white fuzzy hairs.
Leaf DescriptionAlternate, simple, broad-ovate to ovate with an acuminate tip and crenate margins. 8 cm across and 4-7 cm in length. Glossy, dark green on top and pale, light green below.
Flower Description5 petalled, dehiscent white flowers, 5-7 cm across held in inflorescence of 6-12 blooms producing an odorous scent.
Fruit DescriptionSmall, brown, inedible, fruit 2 cm in diameter turning soft in late autumn.
Colour DescriptionColour of foliage varies from glossy, dark green in the summer to red, orange, yellow and purple in the autumn. In spring white flowers in clusters of 6-12 encompass the entire plant. The bark is light brown while the fruit is brown and covered with tiny russet dots.
Texture DescriptionMedium textured in both summer and winter.

Photographs