Q: There is a tree in bloom outside my office and I’m wondering what it is. It has white/green blossoms and looks like a pear tree but doesn’t smell like a fruit tree. It sort of smells like sewage. The smell is similar to a carob tree, but more so. I tried to find it online by googling smelly blooming trees and I think it might be a callery pear.
A: You are correct. The tree in question is a callery pear (Pyrus calleryana). These are ornamental pear trees bred to produce flowers and not edible fruit. They became very popular in the last quarter of the 20th century and can be found in many cities and towns as a street tree. The variety most seen is ‘Bradford’ although there are at least a couple dozen others. The flowers have an unfortunate odor as you noticed and are best observed at a distance. Another unfortunate feature of Bradford pears is their branch structure. The tendency for branches to grow from the trunk at sharp angles predisposes these trees to break in high winds. The one thing this tree has going for it is resistance to fireblight, a disease that affects other pear trees. The newer varieties have been bred for better features but fireblight continues to be a concern.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to tucsongardensage@gmail.com
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