MNN Galleries

11 allergy-inducing pollen producers

By: Russell McLendon on April 21, 2011, 7:30 a.m.

Photo: Dean Morley/Flickr

11 of 13

Timothy grass

Named after Timothy Hanson, an American farmer who popularized it in the 1720s, timothy grass is now widely grown as a forage and hay crop in the U.S. It's also one of the worst early-summer grass allergens, behind only orchard grass, according to Pollen Library.

Habitat: Native to Europe and Asia, and adapted to cool, humid parts of North America

Description: Perennial grass with flat leaves, grows 2 to 4 feet tall

Allergenicity: Severe

Allergy season: June to July

Tips: As with other grasses, timothy grass pollen can be controlled by mowing the plants before they flower. The species isn't heavily grown in urban areas, but it does cross-react with pollen from other grass species.