Seasonal Allergies

Types of Pollens

Tree Pollens and Allergies

Not every kind of tree produces pollen that causes nasal allergies. But enough do to make seasonal allergies from tree pollens a major health issue.

Common Allergy-Producing Trees

  • alder
  • ash
  • beech
  • birch
  • box elder
  • cedar
  • cottonwood
  • cypress
  • elm
  • eucalyptus
  • hickories
  • juniper
  • maples
  • mesquite
  • mulberry (nonfruiting)
  • oak
  • olive
  • orange
  • osage
  • pecan
  • palm
  • poplar
  • sweet gum
  • sycamore
  • walnut
  • willow

Grass Pollens and Allergies

Grass pollen is a common allergen. Yet of the more than 1,000 types of grass that grow in North America, only a few produce pollens that trigger nasal allergies.

Common Allergy-Producing Grasses

  • Bermuda
  • blue (especially Kentucky)
  • brome
  • canary
  • johnson
  • orchard
  • redtop
  • rye
  • salt
  • Sudan
  • sugar beet
  • sweet vernal
  • timothy
  • wild oats

Weed Pollen and Allergies

Weeds are the largest source of allergy-triggering pollens in North America. In late summer and early fall in North America, ragweed pollen is the number one cause of hay fever. A single ragweed plant can produce millions of grains of allergy-producing pollen.

Common Allergy-Producing Weeds

  • cockleweed
  • goosefoot
  • hemps
  • mash elder
  • nettle
  • pigweeds
  • plantain
  • ragweed
  • Russian thistle (tumbleweed)
  • sages (mugworts)
  • sagebrush
  • sheep sorrel
  • smotherweed

For more information about allergies and pollens, see the next page.

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Written by Karen Serrano, MD Emergency Medicine resident at the University of Wisconsin-Madison.

Reviewed by Lisa V. Suffian, MD

Instructor of Clinical Pediatrics in the Division of Allergy and Pulmonary Medicine at Saint Louis Children's Hospital, Washington University School of Medicine

Assistant Clinical Professor in the Department of Pediatrics at Cardinal Glennon Children's Hospital, Saint Louis University

Board certified in Allergy and Immunology

Last updated June 2008