Excessive rain and high temperatures caused all the gardenia blossoms to dry on the trees. Both gardenia jasmine shrubs produced an abundance of flowers but the flowers dried on the trees. They kept their form/shape perfectly; in fact, they look pretty except that they are not white when they've dried on the trees. I picked some of the dried ones and stuffed them into a glass jar then added vegetable oil covering the dried flowers. I didn't know what else I could do with them. The shrub's leaves are healthy and glossy.
Dead head the plants and continue to care for them. Watch for signs of insects or disease as a stressed plant can sometimes become infected.