The unseen rose is one of the dominant symbols of "A Rose for Emily"--hence the use of the word in the title. It is a symbol of love, beauty and romance, and represents Emily herself: a fading flower of days gone by. The color of rose also appears in the final chapter upon the discovery of the valance curtains' "faded rose colour;" the rose also represents death--the color of blood--as in the "blood-kin" relatives that appear just before Homer's disappearance.
Other examples of symbols found in the story:
- Miss Emily's house serves as a symbol of the town's past glories as well as its present state of decay.
- Miss Emily's hair serves as a symbol of the passage of time, from its girlish shortness, cut following the death of her father, to the iron-gray strand that becomes so important in the final chapter.
Both of these questions have already been asked and answered many times here on eNotes. Here are two comprehensive links for you: http://www.enotes.com/rose-emily/q-and-a/tags/title and http://www.enotes.com/rose-emily/q-and-a/tags/symbol