Why do Bradford pear trees smell like...that? Updated Mar 17, 2021; The trees are beautiful. Those Callery pear trees, known regionally as Bradford pears, are large and covered with white, five-petaled flowers, native to China and Vietnam. You’ve seen them bloom and flourish for several weeks in Alabama now, and you likely knew they were here before you ever laid eyes on them. Because, well, they stink. But what is that smell? You can’t quite place it. Not quite harsh or bitter enough to think it’s a dead animal in the vicinity of the tree. No, it’s the tree. It smells a bit rotten, kind of a fishy odor. But why does such a stunning natural creation like the Bradford pear tree smell so bad?