Saguaro National Park has 2 sections, one is the NW boundary of Tucson, Arizona; the other is the SE boundary. In between are the 9000'+ Santa Catalina Mountains inside the Coronado National Forest which forms the northern boundary of Tucson.
There are about 1.9 million saguaros inside Saguaro National Park! Saguaro cactus bloom season is May; each arm may have a couple of dozen in good years. The 3-4" flowers are needed by migrating bats in order to survive their spring crossing of the Sonoran Desert; the resulting fruit is used by many species, especially doves including the migratory whitewing dove.