[ProtectOurFreedom]

I’d wager that suburbia, with its gazillions of non-native plants from all over the world, is a hotbed of unfamiliar pollens.

[Jeff Chandler]

Ding ding ding. We have a winner. Urban and suburban landscaping plants—trees in particular—are male, in order to avoid messy litter from blossoms and seeds. Male plants produce polin.