Pollen allergy is very common in central Oklahoma.
Due to the consistent prevailing winds and central location in the grasslands of North American, there are a large number of trees, weeds, and grasses producing pollen in this region. This pollen is also capable of travelling three to four hundred miles on a windy day.
After the turn of the new year, the tree pollen is the first pollen to be produced. The mountain cedar tree in central and south Texas starts pollinating in late December to January and is carried by southerly winds into central Oklahoma. The other tree species begin pollinating after the cedars and the cottonwood tree is usually the last tree to start pollinating. The tree pollinating season is usually completed by June.
Grasses begin to pollinate in April or May, depending on temperatures and rainfall. The grasses will continue to pollinate until September or October depending on environmental conditions. Bermuda grass is the predominate lawn grass in housing developments in central Oklahoma. Timothy grass is the hay the hayfields stretching into Texas and Kansas.
Weeds are the last plant to produce pollen in the year. The onset of weed pollination is variable depending on temperature and rainfall. The weed pollinating season classically begins in August or September and ends with the first hard freeze in the late fall. However, the onset of the pollinating season can be as early as May if the environmental conditions are right.