Since 1984 I have recorded all flowering plant taxa along a five-mile canyon route that climbs 4158 ft (1267 m) to the summit of Mount Kimball in the Santa Catalina Mountains of southern Arizona. In this flora of vascular plants in the Finger Rock Canyon Watershed, I describe the study area and its six vegetative associations, then discuss the impacts of drought, non-native species, and fire. The annotated flora, primarily based on data collected through 2017, includes information on abundance, distribution, vegetative associations, elevation where found, and months and years blooming. To investigate the effect of elevation on species richness and flowering duration, I divided the trail into five segments, approximately one mile (1.6 km) in length, and have focused primarily on an area about 30 ft (9.1 m) on either side of the trail. The phenological data collected is summarized for each taxon seen flowering from 1984-2017. The flora currently includes 615 specific and infraspecific taxa in 363 genera and 84 families. Although the watershed includes only about 0.6% of the area of the Santa Catalina Mountains, approximately 45% of the known flora of the range has been found here. This is particularly remarkable considering the area I have surveyed on foot is only about 7% of the watershed and less than 0.06% of the entire range.