Cedars-Sinai Blog

Why Am I Sneezing?

Wondering what to blame for your sneezing? A guide to pollen in Southern California

Seasonal spring allergies, or allergic sinusitis, are often caused by the pollen from grasses, trees, and weeds, and are usually the culprits behind that itchy face feeling that comes with each season. As trees, grasses, and weeds release their pollen from the male part of a flower or cone, wind, animals, and insects carry the powdery grains to fertilize other nearby plants of the same species.

We've created a guide of common spring pollen found in the Southern California region that may be the culprit(s) of your itchy or watery eyes, headaches, runny or itchy nose, achy sinus, sneezing, and coughing.

Don't think it's allergies? Read: Is it a Cold or the Flu?

Wondering What to Blame for Your Sneezing?

Here are the most common sources of pollen in Southern California.


Bermuda, Common Timothy, Fescue, Ryegrasses, Soft Brome, Curly Blue, Meadow Fescue, Orchard, Prairie Koeler's

Common allergy causing grasses in the Los Angeles area.

Most types of grass release pollen only when they grow tall. A few types, including Bermuda, notoriously release pollen even when kept short. Perennial rye grass and tall fescue don’t usually flower and release pollen until they’re 12 inches or taller. Grass pollen usually is too small to be seen. Common grass pollen allergens include:

  • Bermuda
  • Common Timothy
  • Red Fescue
  • Curly Blue
  • Meadow Fescue
  • Orchard
  • Prairie Koeler’s
  • Ryegrasses
  • Soft Brome


Arizona Cypress, Eucalyptus, Elm, Oak Mix, Olive, Walnut, Western Sycamore, Arroyo Willow, Big Sagebrush, Glossy Privet, White Mulberry, Ash

Common allergy causing trees in the Los Angeles area.

Tree pollen is very fine and powdery, and can be carried for miles on wind. Common tree pollen allergens include:

  • Arizona Cypress
  • Eucalyptus
  • Elm
  • Oak Mix
  • Olive
  • Walnut
  • Western Sycamore
  • Arroyo Willow
  • Big Sagebrush
  • Glossy Privet
  • White Mulberry
  • Ash


Amaranth, Black Mustard, Sagebrush, Western Ragweed, Wormwood, Bracted Saltbush, Black and Coastal Sagebrush, Deer-Root, Cattle-Spinich, Coyotebrush

Common allergy causing weeds in the Los Angeles area.

They aren’t just a source of frustration for gardeners. Many weeds such as Coyotebrush, Silverscale, and the varieties illustrated here can produce allergy-triggering pollen. Common weed pollen allergens include:

  • Amaranth
  • Black Mustard
  • Sagebrush
  • Western Ragweed
  • Wormwood
  • Bracted Saltbush
  • Black and Coastal Sagebrush
  • Deer-Root
  • Cattle-Spinich
  • Coyotebrush

Click here for a printable Allergen Infographic.