Pollen and Mold Center
Composite or Ragweed Family (Compositae Family) - RAGWEED
Get readings about Ragweed aeroallergens.
Weed pollen is dominant in the Fall.
Ragweed blooms from Mid-July to September.
Ragweed tribes in Missouri:
- Sunflower (Heliantheae)
- Ragweed, Cocklebur, Marshelder, Franseria (Ambrosieae)
- Sneezeweed, Marigold, Feverfew (Helenieae)
- African Daisy (Arctotideae)
- Calendula (Calenduleae)
- Straw Flower (Inuleae)
- Aster, Goldenrod, Groundselbush, Desert Broom (Astereae)
- Ironweed (Vernonieae)
- Dog Fennel, Joe-pye Weed (Eupatorieae)
- Chamomile, Yarrow, Pyrethrum, Chrysanthemum, Wormwood, Sage (Anthemideae)
- Ragwort, Butterweed (Senecioneae)
- Thistle, Burdock (Cardueae)
- Gerbera Daisy (Mutisieae)
- Chicory, Lettuce, Dandelion (Cichorieae)
Facts about Ragweed
- Common ragweed (Ambrosia bidentata) is a coarse, hairy plant with a slightly noxious odor and no pretty flowers.
- There are 17 species of ragweed in North America.
- Ragweed pollen amounts increase with heavy spring rain and hot, dry pollen season. Pollen amounts decrease when rain and humidity is too great during the blooming period.
- Ragweed (Ambrosia bidentata) is the most important
allergenic plant of North America. It produces large quantities of small, buoyant pollen.
- The strongest antigen, antigen E, is found in Ambrosia and Franseria.
- Other strong antigens are found in sagebrushes (Artemisia) and marshelders (Iva).
- Cocklebur (Xanthium) causes occasional allergy problems, but is not abundant in the air.
- Goldenrod (Solidago) is insect-pollinated and seldom an allergy problem.
- Dog fennel (Anthemis Cotula) is partly insect-pollinated, but does have a large amount that is airborne. This blooms late summer to December.
- Eating sunflower seeds, drinking chamomile tea, and smelling pyrethrum insecticide, marigolds, or chrysanthemums have all been reported to cause allergic reactions.
- Wormwood (Artemisia) and mugwort (Artemisia vulgaris) are prevalent in the central states and produce pollen in the late summer and fall.