The blossom of the Saguaro Cactus is the State flower of Arizona, USA. This pure white flower that looks like an industrial strength daisy blooms on the tips of Saguaro Cactus arms during May and June. Individual flowers live about 18 hours. It opens at night and closes the following afternoon. To develop into fruits, they must be pollinated within this time frame. Pollinated blossoms shrivel before growing into a tasty red fruit used to make jams and jellies.