There are several unrelated types of plants that go by the common name “plantain”, including the “cooking bananas”, hostas, and the many small plants in the genus Plantago.[1] The ones where the pollen are of interest are specifically the English Plantain, Plantago lanceolata, which produce a windborne, allergenic pollen[2] . These plants grow commonly in lawns, I see them myself a great deal, like this specimen from our yard that was producing pollens from that ring of anthers popping out of the flowerhead, proceeding from the bottom to the top over a period of days like an extremely slow-motion string of firecrackers :[3]

They are approximately as common as dandelions.Their main blooming season is generally around May and June, which is about the same time as a lot of other pollen-releasing plants, and so they kind of generally contribute to the overall allergenic pollen haze in spring and early summer.

Footnotes