Pollen Information

Pollen Information:

Pollens are the tiny, egg-shaped male cells of flowering plants. These microscopic, powdery granules are necessary for plant fertilization. The average pollen particle is less than the width of an average human hair.

Pollens from plants with bright flowers, such as roses, usually do not trigger allergies. These large, waxy pollens are carried from plant to plant by bees and other insects. On the other hand, many trees, grasses and low-growing weeds have small, light, dry pollens that are well-suited for dissemination by wind currents. These are the pollens that trigger allergy symptoms. Seasonal allergic rhinitis in the early spring is often triggered by the pollens of such trees as oak, western red cedar, elm, birch, ash, hickory, poplar, sycamore, maple, cypress and walnut. In the late spring and early summer, pollinating grasses - including timothy, bermuda, orchard, sweet vernal, red top and some blue grasses - often trigger symptoms.

In addition to ragweed - the pollen most responsible for late summer and fall hay fever in much of North America - other weeds can trigger allergic rhinitis symptoms. These weeds include sagebrush, pigweed, tumbleweed, Russian thistle and cockleweed. Each plant has a period of pollination that does not vary greatly from year to year. However, weather conditions can affect the amount of pollen in the air at any given time. The pollinating season starts later in the spring the further north one goes. Depending on where you live in the United States, the pollen season can begin as early as January (in the southern states). Generally, the pollen season lasts from February or March through October. Trees pollinate earliest, from late February through May, although this may fluctuate in different locations - starting in April in the northern United States to as early as January in the south. Grasses follow next in the cycle, beginning pollination in May and continuing until mid-July. Weeds usually pollinate in late summer and early fall.