Callery Pear

Naming

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.

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, 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 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", they are actually wild-growing descendants of multiple genotypes of "Pyrus calleryana", and hence more correctly referred to by the common 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.

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, many groups have discouraged further planting of 'Bradford' and other similarly structurally deficient Callery pear cultivars in favor of increasing use of locally native ornamental tree species.

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

Uses

Pear wood is among the finest-textured of all fruitwoods. It is prized for making woodwind instruments, and pear veneer is used in fine furniture. Pear wood is also among those preferred for preparing woodcuts for printing, either end-grained for small works or side-grained for larger.

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.