I’m wondering if anyone else has experienced this, with respect to Bradford Pears (Pyrus calleryana), in cases where the tree is flowering:
- Sometimes their smell is overwhelming
- Other times, barely any scent
Related posts:
A photo:
Yes, the ones at my high school had no scent (or maybe a faint, unnoticeable scent) while the ones at my univeristy stank to high heaven. Weird.
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Google search tells me there are many cultivars of Callery pear other than the originally popular ‘Bradford.’ I must conclude some of them have stinkier genes than others, although nothing I read mentioned it.
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I am not familiar with this tree but is it a type with genders like papaya trees, where there are males and females but both flower? The female papaya flower (top photo) has a light scent; the male (bottom) none.
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I would never guesses a pear could smell bad, the tribe has such nice-smelling flowers: apple species, Prunus, regular pear. Why this one smells bad and what it reminds of?
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From Wikipedia: Their dense clusters of white blossoms are conspicuous in early spring, with an odor often compared to rotting fish or semen.[9][10][11][12] According to extension specialist Kelly Oten of North Carolina State University, the smell attracts flies which are the primary pollinators rather than bees.[13]
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Wow, what a comparison, sounds nasty! Very interesting that it’s into flies and not bees, wonder why so, cause regular flowers attract flies too, was there a deficit in bees when it was evolving?
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There are many types of flowers that use similar strategies to attract flies and other decomposers as pollinators. One abstract from the literature:
Johnson, S. D., & Jürgens, A. (2010). Convergent evolution of carrion and faecal scent mimicry in fly-pollinated angiosperm flowers and a stinkhorn fungus. South African Journal of Botany, 76(4), 796-807.
Abstract
Flowers of many angiosperms attract fly pollinators through mimicry of animal carrion and faeces. This phenomenon of “sapromyiophily” is also evident in the sporophytes of some mosses and fruiting bodies of “stinkhorn” fungi, both of which use flies as agents of spore dispersal. We studied the scent chemistry of a stinkhorn fungus (Clathrus archeri) and seven fly-pollinated plant species with foetid odours to determine the degree to which these organisms mimic the scent of carrion and faeces (reference scent samples were collected from rotting meat, a rat carcass and horse and dog faeces), as well as the degree of convergent evolution between the fungus and angiosperm flowers. We found that scents of both the fungus and angiosperms tended to contain compounds typical of carrion, such as oligosulphides, and of faeces, such as phenol, indole and p-cresol. This study provides compelling new evidence for mimicry of carrion and faeces, as well as a striking pattern of convergence in the putrid scents of the fungus and the angiosperms, relative to those of confamilial species. The syndrome of sapromyiophily thus encompasses at least two kingdoms (Plantae and Fungi) and provides an effective means of exploiting flies as agents of pollen and spore dispersal.
yes some of them you can barely smell even if youre right next to it and others you can smell from literally across the street
that scent is a hallmark for the start of spring 
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I know the mechanism, my question is why for this species.
Oh, the Bartlett pear isn’t a species, its a cultivar of the common pear, Pyrus communis. Outside the US it is mostly called the Williams Pear. There is no literature on sapromyiophily in Pyrus, so my guess is it arose as an unintended byproduct of artificial selection.
I think they stink, in more ways than one. Here’s a local initiative. https://www.treebountync.com/
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It’s a Bradfort pear, Pyrus calleryana, an Asian species.
Once again proving that I have less than a full brain!
Okay, this paper, https://www.mdpi.com/2673-4133/4/1/1
which uses iNat data, suggests that P. calleryana is a generalist in terms of pollinators. Bees, flies, moths, whatever pollinators are around.
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Can confirm, here a honey bee pollinating one of the smellier trees:
Interestingly, the petals have a rose-like smell when crushed.
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I’m left wondering what (group of?) horticulturalists, upon smelling the species, thought, “Yeah, this is the one! Perfect for planting urban and suburban landscapes!” Let alone it becoming very popular across the whole of the US.
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I feel the same about Photinia - stinky flowers
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Right? And if it is true some cultivars stink less, I would have expected online descriptions of them to list that as a positive feature!
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Crataegus flowers also smell bad. i see flies and beetles pollinating them. i would guess that since the flowers on both Crataegus and Callery Pears bloom relatively early, they benefit from being able to be pollinated by flies when the bees haven’t emerged from their winter slumber yet. or maybe beetles can pollinate at night when bees aren’t active?
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