UA logo Allergy and Asthma in the
Southwestern United States
Information for patients with allergy and related problems
in the Southwest

Plants Known to Produce Allergenic Pollen in Southern Arizona  
Key to recognition of allergenic plants
(for pictures, click the links) 

Grasses and Weeds    Trees and shrubs                       Return to menu

Common Name Latin Name Flowering Period (Tucson) Comments
Bermuda Grass Cynodon dactylon June-Sept Commonly used in parks, sport fields, a weed in dirt alleys. Nonflowering hybrids available 
Grama Grass Bouteloua May-Oct Several native species.  A common urban and rural weed
Johnson Grass Sorghum halepense May-Dec Grows in washes
Rye Grass  Lolium March-Oct Allergens common to most other grasses
Buffel Grass Pennisetum ciliare Perennial Common, invasive weedy grass, similar to Fountain Grass
Alfalfa Medicago sativa March-June Cultivated for forage.  Blue-violet flowers
Burrobrush Hymenoclea salsola March-April  Botanically related to the ragweed family
Bursage, Slimleaf Ambrosia confertiflora April-Nov Synonym for Ambrosia confertiflora is  A. tenuifolia   (Slender Ragweed)
Bursage, Triangle-leaf Ambrosia deltoidea Dec-April  A type of  ragweed.  Prolific pollen producer. Also known as Rabbit Bush
Carelessweed  Amaranthus palmeri April-Oct A type of pigweed 
Cocklebur Xanthium strumarium August, Sept Large broad leaves, ovoid burs 1/2-1 in long
Iodine Bush Allenrolfea occidentalis July-Nov Mainly in alkaline salt flats and plains of Sagebrush and Mojavean Deserts, Gila and Little Colorado River drainage.  Pickleweed, chico.  Shrub up to 3 ft high.  May cross react with other Chenopodiaceae
Lambsquarters Chenopodium album May-Oct  Widespread throughout N. America
Ragweed, Canyon Ambrosia ambrosioides July-Oct  Leaves 3-5 in long 
Ragweed, Desert Ambrosia dumosa May-Nov White bursage. Throughout Sonoran Desert.  Shrub 2 ft high, leaves 3/4 in long
Russian Thistle Salsola kali May-Nov Widespread throughout N. America.  Also known as Tumbleweed
Sagebrush  Artemisia ludoviciana August-Nov  This allergenic species and many other species of Artemisia grow in the Southwest
Saltbush, Scale Atriplex spp Oct-April  Wingscale, Wheelscale and several other species of Atriplex found in the region

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Disclaimer:   This site is for educational purposes only.  Any information that you have found in this web site is not intended to replace medical care or advice given to you by your own physicians. You should consider consulting your local medical library and other web sites for additional information. 

Comments and suggestions welcome!   Email:
Content Owner:  Michael J. Schumacher, MB, FRACP, The University of Arizona
Updated  2/2012