Tucson Pollen Today and Tomorrow - June and July

Ragweeds have stopped releasing pollen for several weeks.   The onset of hot, dry weather in late May and early June has caused  Ambrosia ambrosiodes (canyon ragweed) and Ambrosia deltoidea (triangle leaf bursage, rabbit bush) to wither.  Mesquite and Cercidium spp (Palo Verde tree) usually stop releasing pollen by mid-June.   Bermuda grass in alleys and roadsides mostly dried up in June, but is reviving and starting to flower with the monsoonal rain this year. Flowering of Olive trees is over.   Allergenic trees that may be important locally and have been flowering in recent weeks include California Pepper Tree (Schinus molle) and   Privet trees and hedges (Ligustrum lucidum).  Schinus and Ligustrum will probably stop releasing much pollen by the end of June.
These native plants that flower in May and early June do NOT release significant amounts of allergenic pollen into the air:  Acacia constricta (white-thorn), Acacia Greggii (cat-claw), Prickly Pear cactus (now setting fruit), Saguaro (in full bloom in early June) and Cholla. 

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 May 2009