How Bradford pear trees became a problem
Bradford pear trees (also known as Callery pears) were once a common choice for landscapers and homeowners. They're beautiful trees for spring flowering, and their foliage turns a vibrant red in the fall — which sounds great, right? But in recent decades, experts have flagged these trees for being invasive to our environment in both Iowa and the Midwest more broadly.
"They weren't on our radar as recently as the early 2000s as being a problem," says Jan Thompson, Morrill Professor in the Department of Natural Resource Ecology and Management at Iowa State University.
Bradford pear trees have been cross pollinating and spreading rapidly — from backyards to parking lots — causing ecosystem imbalances. Thompson says the trees were supposed to be sterile and non-fruiting, but that's not the case — they actually produce seeds that look like miniaturized pears.
After the first frost, the seed coat is softened, and the fruit becomes a popular bird snack, which is then spread to a different location through their feces. Fleshy bird dispersed fruits like these are a big contributor to plants becoming invasive. That said, it's also worth noting that birds also spread the seeds of other plants we find enjoyable.
Bradford pear trees are also "weak wooded," meaning they're prone to falling apart during heavy storms. During the derecho in 2020, many Bradford pear trees were wiped out due to the high winds.
And if that’s not enough, the spring flowers they produce? They stink — really badly.
How to help
According to Thompson, there is only one surefire way to mitigate the problem.
"We need to eliminate the source... the source is the seed, and the only way to eliminate the seed is to eliminate the seed-bearing plant."
Which means, if you’ve planted the tree – you should cut it down. But, if you've planted Bradford pear trees in the past, don't feel bad! Even the experts didn't know these plants would become such a problem.
"We use many non-native plants in our landscapes, and by and large, most of them are fine to use, and that's what we were thinking about the Callery pears," Thompson said.
If you're looking for native alternatives, Thompson suggests mini crab apples, wild plums, red bud, elderberry and downy serviceberries.
Jan Thompson made her comments on Talk of Iowa.
