Pear Propagation

When Bradford pear trees became commercially available in the U.S. in the 1960s, no one foresaw the problems that would accompany them. The Bradford pear, a cultivar of the Callery pear species, was the ornamental tree of choice for many Middle Tennessee homes for decades due to its attractive appearance. But over time, these sought-after flowering beauties became the source of wild and invasive Callery pear trees.

Michael Davie, certified arborist and NTCC board member, says, “They were a fad in landscaping in the ’60s and ’70s when they were the new, beautiful trees on the market. Their profusion of white flowers in the spring and tight, symmetrical lollipop shape made this understory tree a popular choice in both urban and suburban yards.” 

Why Are They Such a Nuisance?

“When the trees are young, they’re a perfect oval shape,” Davie explains, “but when they get larger, they fall apart.” After they reach about 15 years old, the narrow branches of the Bradford become less able to withstand the stress of wind or ice. This poses a danger if they’re planted next to cars, houses or walkways. 

Today, Bradford pears are planted much less frequently, and it has even become illegal to sell them in some areas due to the potential for invasive spread. The trees have few pest problems and can be resistant to local diseases, so they are strong competitors with native trees for space and resources —  creating problems for the animals and insects that depend on native species. 

Callery Pear Cultivars

There are about 25 cultivars of the Callery pear tree (Pyrus calleryana), Bradford being the first cultivar of the genus to be introduced from China. While the Bradford pear tree is bred to be sterile, its flowers can become cross-pollinated with other types of Callery trees and produce fruit. This fruit is then eaten by birds and deposited randomly across landscapes, where the tree grows early in the year and crowds out native species.

Davie says that since Bradford cultivars are sterile, they are reproduced for sale by grafting. “They use the rootstock of another pear tree, usually a Callery, which can give outshoots and produce fertile Callery trees.” He warns against leaving the roots when trees are cut down since they can easily regrow a tree. If you’re removing a Callery pear, make sure to remove the root system as well.

Between fertile roots and pollinated flowers, the Bradford pear, and other Callery trees, have become an invasive species that interferes with and harms local ecological systems. It should be noted that there are no pear trees native to the U.S., although the species of pear trees grown for food (Pyrus communis, the common pear including d’Anjou, Bosc and Bartlett) don’t become a problem the same way that the Callery species does. Some species are just more invasive and able to spread more easily than others.

Native Alternatives

Every spring there are more and more Callery pears popping up in the wild across Middle Tennessee, making it more difficult to get rid of. “They’re becoming a new honeysuckle level of invasive, spreading in places that aren’t maintained, or where they might not be noticed until a bunch of them have popped up.” Davie says, “the genie’s out of the bottle with Callery pears. It will be a battle going forward, but their spread can be slowed down by getting rid of them whenever possible, and replacing them with native species.” 

There are many suitable substitutes for Bradford or other Callery pear trees, including:

• Crabapple

• Flowering Dogwood

• Redbud

• Yellowwood

• Red buckeye

• Magnolia

• Plum

Browse our selection of NTCC-approved trees through our tree sale, and stay up to date with information about Nashville’s local trees by signing up for our newsletter!