• Tree pollen causes most springtime seasonal allergies. It is the first pollen to appear each year in the U.S.
Throughout the nation, trees produce the most pollen from February through June. But in some regions, such as the South, trees may produce pollen as early as December or January and peak at multiple times during the year.
Some trees produce pollen you can see (a fine, yellow dust that covers outdoor surfaces), while other trees produce pollen that is very small and can’t be seen. All tree pollen is usually light and easily carried by the wind.
The most common tree pollen culprits are cottonwood, oak, cedar, juniper, ash, elm, olive, aspen, hickory, pecan, beech, poplar, birch, maple, walnut, alder, box elder, mulberry and willow. At least 10 of those species are found in Oklahoma.
• Grasses cause most late spring and summer pollen allergy symptoms. It is most common from April through early June, but grass pollen can sometimes be found year-round in warmer parts of the country. It can overlap with tree pollen or weed pollen seasons.
When you have a grass pollen allergy, you will experience the symptoms only when the pollen to which you are allergic is in the air.
Even though there are hundreds of types of grasses, only a few cause allergy symptoms. The most common grasses that cause allergies are Bermuda, Fescue, Kentucky blue, Johnson, Rye, Sweet vernal, Orchard and Timothy.
• Among weed pollen allergies, ragweed is the worst offender; ragweed allergy is the most common weed pollen allergy. Approximately 15% of people in the U.S. are allergic to ragweed pollen. Ragweed grows throughout the country, especially in the Midwestern and Eastern states.
Depending on your location, ragweed season may last six to 10 weeks, peaking in mid-September in most areas in the U.S.
Other weed pollen also can cause symptoms. These plants are responsible for causing the most pollen allergy symptoms in the fall: Burning bush, Mugwort, Russian thistle, Cocklebur, Pigweed, Sagebrush, Lamb’s-quarters, Ragweed and Tumbleweed.