The Trees From Hell
By Steve Lagerfeld
Bradford pears began life as a hugely popular hybrid flowering tree. Then they became a limb-shedding hazard. Now they have morphed into a family of invasive trees that are overwhelming open spaces and depriving birds and other wildlife of food. And they’re growing right in the middle of McLean.
It seemed such a wonderful idea! Fifty years ago, in the spring of 1972, a trio of local dignitaries and a small crowd of citizens converged on Dolley Madison Boulevard to celebrate the planting of 113 new trees in the median of one of McLean’s defining streets. They were Bradford pears, a miracle tree hybridized from a Chinese original by U.S. Department of Agriculture researchers and released only a dozen years earlier. The trees burst into bloom in the early spring in an exuberant display of white flowers, grow rapidly, and can tolerate inhospitable conditions. Developers, urban planners, landscapers, homeowners, and others eagerly planted them by the thousands. They had no way of knowing what a terrible mistake they were making.
In fact, there were two mistakes, and the second would prove to be far worse than the initial planting.
It wasn’t long after that glorious spring day in 1972 that the early magic began to fade. The “miracle” tree had a fatal weakness, which became obvious only as it matured. Its branch system is structurally weak, so that large limbs often snapped off and fell to the ground. And the trees have short lifespans—less than 25 years, on average. Before long, the Dolley Madison trees had become not just a nuisance but a hazard to passing motorists.
By 2013, more than half the trees were dead, and the McLean Trees Foundation rallied government and private companies in a volunteer effort to prune the survivors and cut down 10 more dead or dying trees. Today, 36 Bradford pears, some of them in advanced stages of decline, still occupy the Dolley Madison median between Elm Street and Beverly Road.
Even as the Bradford pears were dropping limbs and dying, something else was happening that transformed them from nuisance junk trees into monsters. Plant breeders who recognized the tree’s structural weakness had quickly gone to work to create new, improved cultivars--Cleveland Select, Aristocrat, and perhaps two dozen more. Together with the Bradfords (Pyrus calleryana 'Bradford'), they are all members of the Callery pear species. Each of the cultivars, like the Bradford itself, was “self-sterile,” unable to reproduce through pollination by a similar cultivar. But it turned out that they could readily cross-pollinate and reproduce with other cultivars, including the original Bradfords. And that’s exactly what they did.
The result was an explosion of new Callery mixes. Many had 3-inch-long thorns. They began to multiply. Quickly. Aided by birds that eat their small fruits, the pears began sprouting in fields and pastures, along highways and other roadsides, and anywhere else they could gain a foothold. Today, after only a few decades, they are a common sight throughout the American East and South.
In McLean, not far from the Dolley Madison site, Callery pears have colonized an open field in Salona, the largest single tract of open public land in the community. On a late March day earlier this year, a dozen mature Callery pears flaunted their signature white blossoms in the wind, while around them a dense legion of well over a hundred younger pears, not yet mature enough to flower, threatened a darker future.
“Darker” is not just a metaphor. The aggressive newcomers shade out native plants, including tree saplings. Birds and insects that depend on the native plants are deprived of an essential food resource. The Callery pears provide fruit for the birds, but they host few if any of the native insects that are a far more nutritious food for many bird species. The insects, especially caterpillars, are doubly important when birds are nurturing their young, who need soft foods high in fat and protein.
The Callery pear invasion is serious enough that three states, Pennsylvania, Ohio, and South Carolina, are in the process of banning their sale. It’s still possible to buy these invasives at nurseries in Virginia. Don’t! If you have Callery pears in your yard, consider removing them. Here’s how to identify them, along with a gallery of pretty flowering native trees that can replace them.
Just a few miles from McLean, the Town of Vienna is pointing the way forward. Thanks to an anonymous $20,000 donation, it is removing 27 Callery pears in the median of Nutley Street and replacing them with native trees.
What about the Dolley Madison pears? In 2013, when MTF sponsored the last cleanup of the trees, a local arborist said, “The trees have a short lifespan and don’t age well. The community should consider replacing these trees in the future.” That was almost a decade ago. The future has arrived, and now McLean must get down to the business of fixing its 50-year-old mistake and replanting with trees that will grow into a better tomorrow.