The road to Hell is paved with good intentions. Everyone has heard that saying. But have you ever wondered might be growing next to that road to Hell? Your time for wondering is over. The road is lined with callery pear trees, planted by people who thought they were doing good deeds.
In the interest of being more precise, I will refer to these trees collectively as callery pears, rather than Bradford pears. The distinction will become clear as the story is told.
Late in the 20th century, callery pear (Pyrus calleryana) was little more than a ubiquitous yard and street tree. Folks had varying opinions of them. There were two of them in my yard in the 1990s. The flowers were pretty, but they smelled awful. There were too many low limbs that always seemed to be in the way. But the fall colors were impressive.
Today, as the invasive nature of the tree has become obvious, love for callery pears is becoming a thing of the past. In my travels locally in Georgia, and elsewhere in the country, I see roadside after roadside, field after field, dominated by callery pears. The majority of these trees are less than 15 years old. They have occupied a staggering amount of space in a short span of time. And virtually nothing is being done to stop the spread of callery pears.
Meanwhile, as the original planted trees aged, their design flaws began to show. Many of the cultivars have numerous branches just a few feet above ground level. Mowing beneath such trees is a major chore. If you attempt to trim the tree, you realize that it’s nothing but limbs — where do you start, and where do you finish?
There won’t be many family gatherings in the shade of the callery pear, either, unless everyone is lying down. Stand up, and you risk bonking your head on a branch. Will the tree cast enough shade to help reduce your summer utility bills? Don’t count on that, either. The trees might grow fast, but they do not grow tall.
But wait, there’s more. The plethora of overlapping limbs makes for a weak tree that is at risk of breaking every time the wind blows. Drive around your town after a strong storm, and look for downed branches. If you are in callery pear country, that’s the species of tree you’re most likely to see torn to pieces by the wind.
The Daily Bucket is a nature refuge. We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns spinning around us.
We invite you to note what you are seeing around you in your own part of the world, and to share your observations in the comments below.
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Where did the callery pear come from, and why is it everywhere? Here are two of the better historical articles that I’ve found, and I will quote and paraphrase from both, to the point that Fair Use allows. I encourage you to read both. They’re easy reads, and are simultaneously fascinating and frightening. I like the Washington Post article a bit more. The Culley article softens its tone at the end with a “Nobody could have foreseen” sentiment, with which I disagree.
Scientists thought they had created the perfect tree. But it became a nightmare. (Adrian Higgins, for the Washington Post)
The Rise and Fall of the Ornamental Callery Pear Tree (Theresa M. Culley)
Believe it or not, the story begins more than a century ago in Jackson County, Oregon. The Northwest, led by Jackson County, produced large quantities of pears for the national market. Or it did, until a disease known as fire blight appeared, and decimated orchards. From the Post article:
In Talent, Ore., a plant scientist named Frank Reimer was using a test orchard to work on fire-blight control and found that the callery pear, first brought to the States in 1908, was highly resistant to fire blight and might be used as a rootstock onto which varieties of the European pear could be grafted. The much smaller callery fruit is used to make tea in China but is considered inedible.
Botanists were already scouring China and other countries, searching for Magic Plants that would do Magic Things that our native species could not. China was popular because its climate is similar to that of much of the United States, and many of China’s species are closely related to ours.
In 1898, the United States Department of Agriculture created the Foreign Seed and Plant Introduction Office, whose mission was pretty much what the name implied. The first head of this Office was David Fairchild. From Culley:
In the early 1900s, Fairchild began searching for plant explorers who had the dedication and stamina to tolerate the physical discomforts and social isolation of travelling for months in distant lands. He found Frank N. Meyer (1875–1918), a Dutch immigrant and former gardener who had a deep fascination with plants and saw nothing unusual about walking hundreds of miles on a botanical foray. Meyer eventually spent over ten years traveling across Asia looking for useful and valuable plants, seeking, in his own words, to “skim the earth in search of things good for man.” He eventually sent hundreds of shipments of cuttings and thousands of pounds of seeds back to the USDA. Many agricultural crops grown in the United States today, including certain grains, legumes, and fruits, resulted from Meyer’s collections.
Meyer made his way to China in 1916, and was soon sending samples of various plant species back to the US. But there were no callery pears in his shipments. David Fairchild prodded and pleaded with Meyer, who eventually traveled far from Beijing. A four-day boat ride up the Yangtze River took Meyer to an area where callery pears grew wild.
Professor Frank C. Reimer of the Southern Oregon Experiment Station also traveled to China to collect seeds with Meyer. Quoting Reimer, from the Culley article (and this should be a warning for all future importers of exotic plants):
In its ability to endure diverse and adverse soil conditions, this species certainly is a marvel … I found it growing in all the various soil types … ranging from heavy clays to light sandy soils and disintegrated rock. I found it growing in shallow ponds, along streams, well-drained moist loams, and on very dry poor hillsides and hill tops. In places it was observed where the layers of soil above the bedrock was not more than eight inches deep.
If it can grow everywhere, don’t bring it here!
Meyer endured harsh work conditions, and even civil warfare. He died in 1918 while still in China, apparently by suicide. Meyer’s seeds lived on, and were grown at the test orchard in Talent, Oregon, and also at test facilities in Corvallis, Oregon and Glenn Dale, Maryland.
The native callery pear had one characteristic that made it undesirable as a stand-alone ornamental tree (but was unimportant if used as rootstock). The branches had stout, sharp thorns — technically described as spurs.
Okay, we now know how callery pears were introduced into the United States, and why. But how did the species go from being a test rootstock for pear orchards, to being an overplanted yard tree, to being an ecological menace? And why the name Bradford Pear?
Enter John L. Creech, a horticulturist at the Maryland test facility. He observed one tree out of all the plantings that had special qualities. From the Post article:
The tree was 30 years old when Creech first evaluated it, and judging from his later writings, he was besotted by this specimen. He was struck by its vigor, its handsome, mature spread and its evident ornamental qualities. But a plant’s value lies too in what it is not. This one tree did not have the thorns of other callery pears; it was free of diseases and pests and held together in storms. In selecting this individual to mass-produce, Creech named it Bradford after the station’s former head, F.C. Bradford. This specimen’s resilience in storms belied what would become a major problem with its mass-produced Bradford clones: Tight branch-to-trunk angles and congested branching invited the limbs to break apart.
In 1954, test plantings were done in a Washington DC suburb. Six years later, the Bradford pear (we should really call it the Creech pear; poor Mr. Bradford had nothing to do with it) was released to the nursery trade. Had the Bradford pear, and no other varieties of callery pear, been introduced to the public, the tree would probably be regarded as a minor invasive today. Bradford cuttings were grafted onto the native rootstock of Pyrus calleryana. Thus the above-ground part of the tree was a clone, but each rootstock was genetically different.
Since the Bradford clone was sterile if kept away from other pear species, the upper part of the tree was not the big problem. The problem was the rootstock. It could send up shoots which would bloom, and cross-pollinate with the clones and with commercial pear varieties. And it was this very trap that horticulturists ignored, much to our chagrin today.
My final quote from the Post article. Bolding mine:
On a few grafted trees where the scion had failed, the rootstock had produced suckers that then bloomed. These flowers, with the help of bees, caused the “sterile” street trees to set viable fruit. Creech and Ackerman minimized the problem, saying it was highly localized. Clues to the callery pear’s invasiveness are buried in a journal paper written by Ackerman in 1977, when he announced the introduction of another variety named Whitehouse, chosen because it was more upright than Bradford and better suited to small gardens. But this selection was a fugitive from Glenn Dale, growing as a seed deposited by a bird on a neighboring property; Bradford was one of its parents.
In other words, the Whitehouse variety was an invasive offspring of the Bradford clone. More varieties followed, planted by the tens of millions across much of the United States. The different varieties interbred with one another, and with rootstock sprouts. Oh, and guess what — the escaped trees had the thorny spurs of the original species!
The invasion was slow at first, a few trees along roads and fencerows. When those trees reached maturity, they produced thousands of seeds, which birds carried far and wide. Adjacent lands exploded with callery pears in short order. The growth is now exponential, while the efforts to halt it are incremental.
For example, the Culley article suggests that the commercial production of callery pears should be “carefully phased out,” and
...if homeowners choose to keep cultivated Callery pears growing in their yards, they must take responsibility for ensuring that fruits are not produced.
In other words, let the nursery growers continue to make money off a virulent invasive, and put the onus on homeowners who haven’t the foggiest notion of the species of trees in their yards, or the problems they might pose. Meanwhile, new callery pears sprout by the millions each and every year.
China could hardly have built a better Trojan Horse if they tried. They didn’t have to try. We went and gathered the seeds ourselves, and built the horse with our own labor.
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A tip of the hat to 6412093 (who graciously allows us to call him Redwoodman) whose recent diary, The Dinosaur Tree, involving a much happier story about a tree imported from China, spurred me to finally write this diary. It has been on the back burner for several years. I knew that it would take a long time to put it together. In the time that I’ve procrastinated (checks calorie callery counter) 14,726,878,192 more callery pear trees have taken root.