Callery Pear, Let’s take out the trash

Mother Nature announces early spring with the site of daffodils, the sound of robins, and the smell of rotting fish carcasses. Wait, what? Yes, those early blooming trees that provide white puffs of beautiful flowers come with a lot of consequences, one of which is a stench that is distinctively foul and unique to the Callery pear (Pyrus calleryana) tree. You may know them as the “Bradford Pear.” They have been a part of the landscape for as long as we can remember, so other than the smell what are the issues?

Callery pear was introduced to America with very good intentions by the United States Department of Agriculture during the early 1900s. It was considered a potential aid in breeding fire blight-resistant pear trees for commercial growers. Quickly growers realized the tree, native to China, Vietnam, Japan, Korea, and Taiwan, was a fast grower and tolerant to a range of poor soil conditions. Surely it was the perfect ornamental tree for cities across the nation! By the 1960s, the Bradford cultivar was developed as a variety of Callery that could not pollinate itself and it was heralded as the perfect street tree. If every Callery was a Bradford, even the seeds produced could not pollinate a neighboring Bradford, but with time it was discovered that the Bradford has a serious drawback. Its branch structure is weak. Heavy snows, ice, winds and age (typically only about 20 years) cause the trees to break apart. Since Bradfords commonly were used in residential yards and along city sidewalks, this became a serious concern and additional varieties were created that were considered stronger. If only this were the end of the story and all we had were strong and stinky early bloomers across the landscape, this post would end here.

Unfortunately, genetic modifications allowed the creation of a number of new varieties, but these modifications and additional varieties also make it possible for the trees, including Bradford, to easily reproduce. The only requirement for reproduction are two different varieties near each other. So here we are, more than 100 years after the initial introduction to the United States and nearly 60 years after it became popular as an ornamental tree, and the Callery pear is taking its toll on our landscape and our ecosystem. Since it is not native to the United States, the Callery pear does not benefit our native birds, bees, caterpillars, moths, or butterflies. Although the tree has been in this country for over 100 years and that may seem like a long time to humans, it does not compare to the amount of time it takes for evolutionary change. Our native pollinators will completely vanish from a lack of useful plant material before they have time to evolve to the non-native materials introduced to our country.

Today Callery pear is considered one of Kentucky’s (and many other state’s) most devastating invasives. Their ability to aggressively spread has allowed them to crowd out native plant species and take over forested areas. Even a small sapling can produce seeds within three years of development. Since they are an early bloomer, they have little competition for seed dispersal by birds. They also are not eaten by deer, which is a huge advantage over a large percentage of other plant material. Rapid growth allows the trees to take over open spaces, such as grazing land for livestock and wildlife (in Kentucky specifically reducing habitats for wild turkey and Bob White) and create thickets quickly. In addition, merely cutting down trees does not solve even an isolated problem. Small pieces of roots and cut trunks quickly resprout. Cut portions should be treated immediately with an herbicide and any regrowth with leaves should be treated as well.

The next time you see a Callery pear I challenge you to see just one. Even in the front yard of a subdivision, look across the street or down a nearby property line or utility corridor and you will see its offspring. Maybe the smell alone should have been a tipoff to our ancestors that the Callery pear is trash. Today it is our responsibility to take out the trash and remove this tree from the landscape. Of course this also means no longer planting Callery pear or any of its cultivars and that is another problem altogether. If the tree is so horrible, then why do nurseries still sell them? The answer is simple, people still purchase them and they purchase a lot of them every single year.  While some small nurseries have stopped selling the Callery pear because it is harmful, larger nurseries and corporate stores keep the tree in stock because it is a moneymaker. It is profitable for the retail and wholesale sellers and also for the growers themselves, some of which have been growing Callery pear trees since their popularity as an ornamental tree began.  It takes public outreach and education to change something that is so engrained – which is why we are writing about them, again. We thought we were finished writing and warning about pear trees, but every year we still see people promoting and purchasing them. Removing something harmful also is easier when it is replaced with something good.

Rather than just remove them from yards and nurseries, let’s replace Callery pears and the demand for them with native trees and shrubs that DO benefit our pollinators and our ecosystem. Around 95% of bird species use butterfly, moth, and spider larvae to feed their offspring. In addition, many adult birds consume them as well. That is a lot of bird food. Below is a list of flowering plant material that is native to Kentucky and the number of lepidoptera (butterfly and moth species) they support. In case you were wondering, the Calley pear supports zero.

Native Tree Number of supported lepidoptera
Flowering Dogwood (Cornus florida) 118
Eastern Redbud (Cercis canadensis) 19
Carolina Buckthorn (Frangula caroliniana) Native buckthorns support 10
Native Crabapple (Malus angustifolia) 308
Wild cherry, wild plum (Prunus serotina, Prunus americana) 283
Witchhazel (Hamamelis) 63
Hawthorns (Crataegus) 168
American Hornbeam (Carpinus caroliniana) 68
Native Viburnum 100+
Ironwood/Eastern Hophornbeam (Ostrya virginiana) 94
Serviceberry (Amelanchier) 124

 

 

Sources:

https://wildones.org/wp-content/images/NativeCaterpillarsMothsButterfliesHostNativeWoodies.pdf

https://chicagolivingcorridors.org/resources/creating-native-habitat/plant-lists/woody-plants-for-birds-lepidopteran-host-plants/

https://www.caterpillaridentification.org/caterpillars-by-state-listing.php?reach=Kentucky#:~:text=There%20are%20a%20total%20of,and%20are%20labeled%20as%20such.

https://www.invasive.org/alien/pubs/midatlantic/pyca.htm#:~:text=Callery%20pear%20was%20imported%20multiple,devastating%20the%20commercial%20pear%20industry.

https://www.msn.com/en-us/news/us/callery-pear-causes-issues-in-landscape-and-pastureland/ar-BB1fz9Tw