Spring to Fall
All species are wind-pollinated and usually produce large amounts of pollen. These plants are likely cause of allergy.
The most important allergenic plants are the grasses which are members of the largest family of wind-pollinated plants (POACEAE). The most pollination occurs during the summer months, like June to July in Northeast region, but there are few exceptions. Northwest region sees grass pollen earlier, peaking in June. Midwest region has the highest volumes of grass pollen in July. Southern states have a more prolonged and severe grass pollen season, with Southeast region the worst. It may last up to six months in Texas, Arizona and New Mexico with June to August being the worst time for grass allergy sufferers.
The shaded areas on the map indicates where the genus has been observed in the United States.
Enter a full or partial species name to find more information on one of over 1,200 potentially allergenic plants.
For example, you can find chenopods searching on "cheno"