There is no botanical definition for a weed. In common usage, a weed is any plant growing where it is not wanted. To a home owner it could be clover growing in a Bermuda grass lawn and to a farmer it could be sunflowers growing in a wheat field. In the allergy community, a weed is a group of allergenic plants that are neither grasses nor trees (or shrubs). This it the definition that is used here.
Ambrosia (ragweed) pollen is the most important weed pollen seen in Tulsa air samples from late August through early November. Click on the link for detailed information about this aeroallergen.
Pollen grains from the weeds listed below are also contributors to airborne pollen levels in Tulsa.
In addition to ragweed and the other weeds listed above, we sometimes see other types of weed pollen in our air samples. These include pollen from the Apiaceae (carrot family), other Asteraceae (sunflower family), Cannabis/Humulus (hemp/hops), Juncus (rushes), Typha (cattails), and Xanthium (cocklebur). While not abundant in our air samples, these pollen types may be more abundant in habitats where the plants are growing.