White flowering pear trees: so pretty and so invasive

Pear trees cross-pollinate with other trees and spread like wildfire. Photo by Denny Wendell

I’m sorry, but you’ll never look at those white flowering trees the same after you read my column this week. Those beautiful trees (but smell terrible, right?) have turned out to be an environmental disaster.

Ohio put the pear trees on the invasive species list in January 2018. You are probably asking yourself what damage can these trees possibly do? The answer is plenty.

The Callery Pear was introduced in 1964 by the U.S. Department of Agriculture. American horticulturists started selective breeding these trees for stronger branches (pear trees have very weak branches) and shape. This is how we got the Bradford Pear, Cleveland Select and Aristocrat. The trees are fast growing, low maintenance, have a nice shape, and produce beautiful spring flowers, which is why they quickly became a popular choice. 

The pear trees were thought to be sterile – but as it turns out while they cannot reproduce with each other, they are capable of cross-pollinating with any other tree of the same species even if they are genetically different. As these pear trees kept popping up along forest edges and in wetlands, the environmental alarm started sounding.

Still, you may ask “what is the problem?” Well, the pear trees are one of the first to bloom and one of the last to lose leaves, so they are crowding out native hardwood species such as maples and oaks. This is the number one biggest problem with them: They are spreading so fast that our native species are not able to survive.

Second, when pear trees pollinate with other trees, they turn back into the Chinese Callery pear tree which has thorny thickets and are difficult to kill and get rid of. Pear trees only live to be about 20-25 years, and with their weak branches, they eventually become structurally unsound and unsafe. Lastly, the white flowers, while pretty, are super stinky. 

What should you do? Cut your pear trees down. Yes, I’m serious. Just get rid of them now and plant a native species in its place. As I say in all of my columns, you alone can make a difference.

Cutting down your one or more pear trees will help this problem. Your pear tree is cross-pollinating with other trees and spreading like wildfire. Just get rid of it and be a part of the solution.

Some cities are even taking extreme action. Lebanon, which is located in southwest Ohio, has cut down all of the city-owned pear trees and is encouraging residents to follow suit and plant native species instead.  

What native species would be a good alternative? Please visit www.audubon.org/native-plants and you can enter in your zip code for lists of native plants. You can then sort by the type of plant you are looking for such as trees, shrubs, annuals, etc.

I did a quick search for our area and found a few trees that may be good replacements for the pear trees. The Allegheny Service-Berry, the American Plum, the Cock-Spur Hawthorn, or the Easter Wahoo are all smaller, flowering native trees to our area.

Why not plant a Japanese Maple or some other non-native ornamental type of tree? While those trees are not invasive like the pear trees, they still are not native. It is important to plant native species as it protects our biodiversity. Alien ornamental species support 29 times less biodiversity than native ornamentals.

Local birds need insects to survive. Insects live on trees. As an example, native oak trees have been found to host over 500 species of caterpillars; Ginkgo trees host only five. Keep in mind that it takes over 6,000 caterpillars to raise one brood of chickadees, and song birds are in decline.

In conclusion, cut down your pear trees, plant a native tree, and enjoy not only being a part of the solution and helping a bigger cause, but also the biodiversity and song birds you just invited to your yard!

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Volume 11, Issue 9, Posted 2:30 PM, 05.06.2019