What's that smell? Invasive pear trees blooming in Oklahoma, elsewhere
COLUMBUS, Ohio (WCMH) – As warm weather returns to Oklahoma, so does a distinctive springtime odor that many liken to rotting fish. The overwhelming aroma is the result of an invasive species that is illegal to plant in the state.
The Callery pear tree, which comes in multiple varieties, including Bradford pear, Autumn Blaze and Cleveland Select, is native to Asia and is now considered an invasive plant in the U.S. The tree, primarily grown for its appearance, was introduced to North America in the 1900s for agricultural use.
They can now be found in the eastern part of the U.S., "from New Jersey to Illinois and south to Texas," according to Invasive.org, a project associated with the U.S. Department of Agriculture.
Characterized by its white flowers, the tree quickly became popular in landscaping due to its adaptability, color and shape, according to the Ohio Department of Natural Resources. But the tree has become well-known for something else – its odor. The tree’s blooms typically have a strong unpleasant aroma, which can be likened to rotting fish or puke.
As of Jan. 1, 2023, the tree is illegal to sell, grow or plant in Ohio due to its invasiveness. This means nurseries and garden centers are not allowed to sell the trees and homeowners and landscapers cannot purchase or install them.
Ohio is not the only state to ban the Callery pear tree; Pennsylvania and South Carolina have passed similar bans that go into effect this year.
The tree poses a “major threat” to native grasslands and wildlife, according to the Minnesota Department of Agriculture. It can rapidly fill in gaps in open spaces, which leads to the trees crowding out native plants and disrupting ecosystems.
The tree was bred to be sterile and originally believed to be unable to reproduce, however, different varieties of the tree have cross-pollinated, leading to the spread of fruit-bearing trees.
"Its success as an invader results from its capacity to produce copious amounts of seed that is dispersed by birds and possibly small mammals, seedlings that germinate and grow rapidly in disturbed areas and a general lack of natural controls like insects and diseases, with the exception of fire blight," as stated on Invasive.org.
Tiny, hard, brown pears appear on Callery pear trees in the fall. After they are softened by frost, they can attract birds that like to eat the fruit, according to the Minnesota Department of Agriculture. They are, however, inedible for people.
The tree’s messy fruit and weak branches are also among its undesirable qualities.
Ohioans who have a Callery pear tree in their yard are not required to remove it, but removal is encouraged by the Department of Natural Resources. The agency recommends serviceberry trees, eastern redbuds, American plums and flowering dogwoods as potential alternatives.