Desert Ragweed (Ambrosia dumosa)
Desert Ragweed is a small shrub (2 ft) found throughout the Sonoran desert. It is dormant throughout most of the year but comes to life during the spring, particularly if winter rains have been substantial, sprouting leaves and flowers until the heat of summer sets in. In some areas, depending on rainfall and elevation, Desert Ragweed may pollinate in the fall as well as spring. It is one of the most prevalent varieties of Ragweed in South Mountain Park and desert areas surrounding Ahwatukee.