Rose

A rose was, according to Rose Tyler, "a sort of plant". (TV: The End of the World) The smell of roses was a desirable scent that the Fifth Doctor found "quite peaceful". (TV: Castrovalva) The flower was also considered beautiful and wondrous, although, as the Eleventh Doctor put it, "every rose has its thorns". (TV: The Doctor, the Widow and the Wardrobe)

On Dark Space 8, Nicky Newman bought some roses for Mel to make up for his earlier behaviour. (AUDIO: Bang-Bang-A-Boom!)

Also, the Zero Room is the Doctor's TARDIS smells of roses for reasons even unknown to the Doctor