Tucson Pollen Today and Tomorrow - December

Seasonal pollen counts are decreasing with the arrival of cooler temperatures.  Amaranthus palmeri (Carelessweed, one of the pigweeds) has been flowering extensively throughout Tucson in October and is now mostly dead, except in moist roadside soil conditions.  Salsola (Russian Thistle or Tumbleweed) is continuing to flower.   Ambrosia ambrosiodes (canyon ragweed) and Ambrosia deltoidea (triangle leaf bursage, rabbit bush) are green and  growing mainly in the foothills but are not flowering at present.

Grasses have been flowering for several months.  The noxious weeds  Pennisetum ciliare (Buffel Grass) and Pennisetum setaceum (Fountain Grass) have matured and are continuing to flower.  Bermuda grass (Cynodon dactylon), established in alleys and roadsides, is dying off with the cold weather and continues to flower only where it is irrigated.   Grass pollen is expected to decrease in December and January.

Baccharis (Desert Broom) has been releasing pollen from the male flowers, and the tufted seeds maturing in the female flowers will fly in the wind this month.   Mold counts are expected to decrease this month. 
 

Note:  This information is based on ongoing observation of flowering allergenic plants in the Tucson metropolitan area, and not on pollen counts.   Appearance and persistence of any particular airborne pollen species in the air usually lags behind the onset of flowering of the plant of origin.                                                                        Back

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: schumach@u.arizona.edu
Content Owner:  Michael J. Schumacher, MB, FRACP, The University of Arizona
Updated 12- 3-06