According to this regional allergy guide, the U.S. is divided into eight sections based on allergens and pollination times. During the late spring and summer months, tree pollination is ending, ushering in grass and weed pollen season and a host of allergy symptoms.
California, Oregon, and Washington’s tree (walnut, rye, and cedar) pollination season ends at the beginning of July. Grasses like bluegrass, Bermuda grass, orchard, wheat grass, and sweet vernal start spreading their seeds in March and don’t stop until November. Ragweed, sage, and chenopod can also cause problems all the way until November.
In Texas and Oklahoma, troublesome trees like cedar, oak, and elm pollinate until June. Grass season, which includes culprits like Bermuda and quack grass, lasts until September. Similar to the Pacific region, ragweed and chenopod are the main weed allergens in these states.
This region includes Utah, Nevada, Wyoming, Colorado, Montana, and Idaho. May is the last month for maple, cedar, and oak trees to cause allergies here. Starting in April, grasses such as wheat grass, redtop, orchard, and Bermuda begin pollinating and keep going until July. Weed season starts in June, with ragweed and tumbleweed targeting people until fall.
Like the Mountain area, Nebraska, Kansas, and the Dakotas come to the end of tree season—offenders include birch, hazelnut, oak, and maple—in May, just in time for grasses like wheat grass, brome, and orchard grass to start pollinating. Grass season ends in July, which is when weeds like ragweed, nettle, and plantain take over.
Minnesota, Michigan, Missouri, Indiana, Wisconsin, Ohio, Iowa, and Illinois deal with pollen from elm, birch, alder, oak, and hickory trees until the end of June. Grasses like rye, Bermuda, redtop, and fescue cause the most allergies between May and July. Mid-summer is when weed season starts here and includes the same problematic weeds as the Plains region.
People mistakenly think that the desert region is less prone to allergies, but that’s a myth. The tree pollination season ends in the spring in New Mexico and Arizona, but grass season, which includes brome, salt grass, rye, and June grass, is in full swing until October. Ragweed, sage, and chenopod began pollinating in March and will continue to do so until December.
The Southern states in this region—the Carolinas, West Virginia, Virginia, Florida, Kentucky, Tennessee, Mississippi, Georgia, Alabama, Florida, Louisiana, and Arkansas—have a short tree season that ends in June. However, grass season lasts practically the whole year; Bermuda, redtop, vernal, timothy, and saltgrass are the main allergen sources. Weed pollination starts in June and shares the same offenders as the Great Lakes and Plains regions.
In this region (which includes New Hampshire, Maryland, District of Columbia, Rhode Island, Connecticut, New Jersey, New York, Delaware, Vermont, Pennsylvania, and Massachusetts), trees such as oak, juniper, pine, and birch wreck the most allergen havoc from February until June.
During the summer months, mold spores proliferate due to the hotter temperatures and cause allergy symptoms as well. They’re found all over the country, particularly in grass, compost, leaf piles, forests, soil, and other wet or damp areas.
So now that we know the types of pollen to blame for our allergies, how can we avoid allergic symptoms as summer edges nearer?
- Allergens are most prominent in the morning (usually between 5 a.m. and 10 a.m.), so limit outdoor time until later in the day
- Foods like apples, carrots, and pears and coffee can make symptoms worse for some people, so be aware when eating them
- Close house and car windows
- Keep clear of large grass piles—hey, it’s a way to get out of mowing the lawn!
Pollination is a necessary and unavoidable part of nature, just as our bodies’ reaction to pollen—releasing histamine, which causes allergy symptoms—is natural and largely unpreventable. But by knowing our allergen enemies and following the steps above, we can minimize our exposure and spend summer sunning by the pool instead of being stuffy and miserable.