It’s that time of year when you’re hungry for green, searching for reassurance that spring is near. The Callery pear tree delivers in late March/early April in the Chicago area, peppering landscapes and swallowing fields and woodlines. It’s everywhere and a clue to it’s invasive nature. It’s the first glimmer of spring we often see in our area and when I worked for a tree nursery several years ago, the most common question I got from customers this time of year was, “What is that beautiful white tree I see everywhere?” And then… “Do you sell it?” People couldn’t get enough of it and when you don’t know much about trees, it’s easy to give into the squeakiest wheel. It seems like a safe, reliable choice.
Don’t fall for it! BIG mistake.
In an effort to bring awareness, I covered the spread of the Callery pear for a video on my Here She Grows YouTube channel which you can view here. Many who watched it said they had no idea how invasive it was and lamented that they had recently planted one in the last few years. Several asked why the tree was still being grown and sold by reputable nurseries. I have no idea. Continuing to grow and distribute trees, plants and shrubs that are swallowing up natural areas at warp speed is an ethical issue. Which makes me wonder. Do tree nurseries ignore the invasive species list?
Every big box store carries Callery pear this time of year. Cleveland Select, Bradford, and Chanticleer are the most common cultivars found at garden centers in my area. The bigger issue is why those in the tree nursery trade continue to grow it here in Illinois and anywhere east of the Mississippi. I suspect it comes down to lack of awareness and simple demand. It’s a sure thing. Sure to sell and sure to swallow up everything around it. Which means the tree trade can continue to throw down seed, knowing they’re certain to sell their trees to an ignorant consumer.
After watching my YouTube video and seeing my Instagram stories, many of you asked how plant scientists could get it so wrong. Here’s what happened…
Pear orchards across California and Oregon in the early 1900s were huge, with an estimated worth of $10 million. Fire blight, a highly infectious bacterial disease found in the Rosaceae family, put an end to it, decimating orchards and forcing plant scientists to seek out blight-resistant pear trees. They discovered that Callery pear was highly resistant and began using it as a rootstock for grafting on European pear varieties.
Callery pear seed collected on expeditions to China was planted in a test orchard in Oregon where they would grow for 30 years before being discovered by horticulturist John L. Creech. He admired the tree for its form and resiliency and decided to trial it, planting 180 of them in a treeless Washington suburb notorious for poor soil in 1954. He named them after a colleague, F. C. Bradford.
Six years later, he released the Bradford pear to the industry, offering growers a Bradford scion to be grafted onto a Callery pear. While the scions were genetically identical, each Callery pear rootstock had it’s own identity. If the grafted scion failed, the Callery pear rootstock suckered and flowered. The bees were more than happy to pollinate the surrounding sterile pear trees. The result…viable fruit.
Callery pear quickly became the 1960s poster child for suburban sprawl across the United States, lining the streets of most new housing developments from California to New Jersey. The tree seemed to have it all – white flowers that popped earlier than other trees in the spring, glossy foliage that turned gorgeous shades of red and orange in the fall, and most importantly, it grew anywhere. Acid or alkaline, wet or dry soil, Callery pear was unfazed.
By the 1980s, about a dozen “sterile” varieties of Callery pear had been developed by the nursery trade. Individually, they were sterile. But when introduced to another variety, capable of producing an entirely new tree with heavy fruit set. Birds gobbled it up, dropping small bombs, each with their own unique genetic code, across the country like wildfire. To date, the Callery pear is invasive in 29 states and still sold at most big box stores and many tree nurseries.
So I challenge you to find a new tree, a better one. Spread the word. Start here.