Pollen

Plants release tiny pollen grains to fertilize other plants of the same species. Most of the pollen that causes allergies comes from trees, grasses, and weeds. The pollen travels by the wind and find their way into your eyes, nose and lungs, causing allergy symptoms if you have a pollen allergy. Pollen allergy symptoms include stuffy nose, sneezing, coughing, and itchy, watery eyes.

Tree pollen is often the first to appear each year in Colorado. It also often overlaps with grass pollen in the spring and summer. Some of the trees that cause the most allergy symptoms are:

• Alder, Ash, Aspen, Beech, Birch, Box elder, Cedar, Cottonwood, Elm, Hickory, Juniper, Maple, Mulberry, Oak, Olive, Pecan, Poplar, Walnut, and Willow

Grasses cause most late spring and summer allergy symptoms. There are hundreds of types of grasses, but only a few cause allergy symptoms. Some of the most common types are:

• Bahia, Bermuda, Fescue, Johnson, Kentucky blue, Orchard, Rye, Sweet vernal, and Timothy

Weed pollen, especially ragweed, appears in the late summer and fall. Ragweed is an invasive annual weed and can travel hundreds of miles in the air, which makes it hard to avoid. Common weeds that can cause symptoms include:

• Burning bush, Cocklebur, Lambs’-quarters, Mugwort, Pigweed, Ragweed, Russian thistle, Sagebrush, and Tumbleweed

Flowering plants that spread their pollen by insects, like roses and some trees, do not cause seasonal allergies.