In "Dr. Heidegger's Experiment" by Nathaniel Hawthorne, the rose symbolizes the passage of time and its effects. At first the rose, that has been given to the doctor by his fiancee fifty-five years ago, shows all the effects of time "...though now the green leaves and crimson petals had assumed one brownish hue..."
And his old friends are depicted "...They looked as if they had never known what youth or pleasure was, but had been the offspring of Nature's dotage, and always the gray, decrepit, sapless, miserable creatures, who now sat stooping round the doctor's table, without life enough in their souls or bodies to be animated even by the prospect of growing young again ..."
Through the changes that the rose suffers, after been put in the water from the Youth Fountain, "...The crushed and dried petals stirred, and assumed a deepening tinge of crimson, as if the flower were reviving from a deathlike slumber; the slender stalk and twigs of foliage became green; and there was the rose of half a century, looking as fresh as when Sylvia Ward had first given it to her love..." so we can predict what will happen to the guests. "...Assuredly there was an almost immediate improvement in the aspect of the party...together with a sudden glow of cheerful sunshine brightening over all their visages at once. There was a healthful suffusion on their cheeks, instead of the ashen hue that had made them look so corpse-like..."