The Callery Pear: Stinky and Invasive

The pyrus calleryana is a very beautiful tree, but it has a couple of faults—mainly, its stinky, bodily fluid-like smell. Karrah Toatley has more.
WNUR News
WNUR News
The Callery Pear: Stinky and Invasive
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SPRINGTIME IS UPON US AND IT’S TIME TO STEP OUT AND SMELL THE FRESHLY BLOOMED FLOWERS. 

OR MAYBE NOT. 

HAVE YOU BEEN WONDERING WHY IT SMELLS SO BAD LATELY? WELL, IT’S BECAUSE OF THIS CERTAIN TREE. THAT TREE IS THE PYRUS CALLERYANA OR THE CALLERY PEAR. 

THE CALLERY PEAR CAN GROW UP TO 40 FEET TALL AND HAS WHITE FIVE-PETALED FLOWERS THAT ARE HELD TOGETHER IN A BALL-SHAPED BUNDLE. DESPITE ITS SMELL THE TREE IS KNOWN FOR ITS BEAUTY. 

 HOW COULD SUCH A PRETTY TREE HAVE A SMELL REMINISCENT OF A GUY’S HIDDEN SOCK? 

[Alison Branz] My name is Alison Branz, I’m in the plant biology and conservation program at Northwestern and Chicago Botanic Garden. 

[AB] That stinky smell comes from their flowers in the spring, and since the ornamental pear isn’t native to Illinois, that stinky smell function is kind of unknown a little bit. 

THE KEY WORD HERE IS A LITTLE BIT.

[AB] When flowers smell a certain way it’s meant to attract a certain pollinator. But since it’s not from here it doesn’t have that pollinator that it evolved alongside where it originally came from in Asia. 

THE CALLERY PEAR IS AN ORNAMENTAL PEAR TREE NATIVE TO ASIA. IT WAS INITIALLY INTRODUCED IN NORTH AMERICA DURING THE EARLY 1900S. 

BUT WHY BRING IT OVER HERE? 

[AB] It was brought here for its ornamental value. People really like that compact like egg shape of the canopy and the full canopy of flowers that we’re seeing right now in the spring. 

ORIGINALLY THE TREE WAS BROUGHT OVER FOR AGRICULTURAL USE BUT QUICKLY BECAME A FAVORITE IN THE LANDSCAPING INDUSTRY DUE TO ITS ADAPTIBILITY, FLOWERING, FALL COLOR, AND ROUNDED CROWN. 

WHILE THE TREE WAS BROUGHT HERE FOR ITS AESTHETIC APPEAL, THE UNPLEASANT ODOR IS NOT THE TREES SOLE DISADVANTAGE.

[AB] When it was introduced here, it was meant to be totally harmless in that regard. It can’t pollinate itself, but it cross-pollinates with other pairs so it can get pollen from other pear trees, and then it can form viable seeds in the little fruit that it produces. 

THEN NATURE DOES THE REST .

[AB] The birds eat them, and then fly around and poop those seeds out all over the place. 

WHY IS THIS SO BAD THOUGHT, BESIDES THE WHOLE SMELL PART, OF COURSE? IT’S BECAUSE THE BIRDS ARE SPREADING THEIR SEEDS TOO MUCH TO THE POINT THESE STINKY TREES ARE PROPAGATING LIKE CRAZY IN AN AGGRESSIVE WAY. 

[Patricia Hayes] My name is Patricia Hayes. Everyone calls me Pat. I’m a volunteer site steward for Orland Grassland Land and Water Reserve. 

THE ORLAND GRASSLAND LAND AND WATER RESERVE IS APPROXIMATELY 1000 ACRES OF ROLLING UPLAND, SWALES, WETLAND, SHRUBLAND OAK SAVANNA, AND WOODLAND. WITH ABOUT 970 ACRES OF OPEN, CONTINUOUS PRARIES SURROUNDING SUBURBIA AND FARMS IN SOUTHWEST COOK COUNTY.

 BUT IT IS ALSO WHERE A HUGE OUTBREAK OF CALLERY PEAR TREES CAN BE FOUND. 

[PH] The Callery Pear likes to land in open spaces, so what will happen is, the birds that are common to both landscape areas and open areas such as our thousand-acre prairie, bring this calorie pair in a ton.

BOOM! AN INFESTATION OF CALLERY PEARS.

[PH] The problem with Callery Pear is it becomes very, very, very dense, very, very, very quickly. And it obliterates the ecosystem that is there.

INCLUDING BUT NOT LIMITED TO THE GRASSLAND BIRD.

THE GRASSLAND BIRDS ARE BIRDS THAT NEST IN OPEN AREAS DOMINATED BY GRASS INSTEAD OF TREES. MANY GRASSLAND BIRD SPECIES ARE EITHER ENDANGERED OR THREATENED SPECIES.

THE CALLERY PEAR IS NOT HELPFUL EITHER. THE TREES ARE CAUSING THEIR NESTING AREA TO BECOME SO DENSE, THESE BIRDS HAVE NO PLACE TO SETTLE DOWN.  

SO HOW DO WE GET RID OF IT?

[PH] The best strategy that I know is to go through and either foil or spray the small ones. If it’s taller though, then you wanna cut it and you wanna dab it with herbicide or basal bark or something like that. You let them die out and then the following year you run a prescribed burn over the top so that it will, take care of anything that is dead. And burn it up. And then if there are tiny little samplings, the fire may discourage them from propagating.

SIMPLE RIGHT? 

WRONG, THERE IS ALWAYS A CATCH.

[PH] Even if we took out every tree, as long as the surrounding area is so full of Callery Pear, it is just gonna come back.

DESPITE THE PROBLEMS ASSOCIATED WITH THIS INVASIVE TREE ITS STILL A HIT IN THE HORTICULTURE INDUSTRY.

WAIT, WHAT IS HORTICULTURE? 

[AB] Horticulture is the production of plants for human use, but with an emphasis on just enjoying their beauty. 

[AB] Some of the habits in the horticulture industry don’t really align with the ecological point of view that we should be considering. 

WHICH IS WHY PEOPLE LIKE PAT ARE WORKING SO HARD TO CHANGE THAT. WHICH STARTS IN TWO WAYS. ONE IS THROUGH LAW.

[PH] We need for the state of Illinois to designate this as a noxious plant.  if you get it designated as a noxious weed, then you can’t buy it and you can’t sell it, and you can’t have it. 

THE OTHER IS THROUGH EDUCATION.

[PH] Education is very, very necessary because you need the public support. 

GETTING PUBLIC SUPPORT IS HUGE BECAUSE ITS THE PUBLIC THAT WILL BE LOSING THEIR PRECIOUS TREE. THE COMMUNITY NEEDS TO UNDERSTAND THE NEED FOR THEM TO HAVE THEIR CALLERY PEAR TREES  SWAPPED OUT, BECAUSE THESE TREES ARE DOING TOO MUCH DAMAGE TOO FAST TO BE WORTH THEIR AESTHETIC APPEAL. 

[PH] I’ve been doing this for 20 years and there are plenty of things out there, but I’ve never seen anything come and take over so completely as this tree has done

[Music: “Little Voices”] 

FOR WNUR NEWS, IM KARRAH TOATLEY. 

Music track: Little Voices by Amine Maxwell

Source: https://freetouse.com/music  

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CORRECTION 5/18 — An earlier version of this story misspelled Alison Branz’s name as “Alison Brands.”