Joy is a character who appears in the Season 8 episode "Mr. Monk Is the Best Man where she was the owner of Affinity, a flower shop where the missing person worked. Joy, confirms that Charlie Doyle has been missing since the same time that the body turned up. When asked to see the man's records, Joy admits that she employed him "off the books," and didn't ask for anything from him in the way of identification or history.
While they are talking, she shares her private belief that everyone has a flower that fits them perfectly. She picks one each for Natalie and Randy, then, after some difficulty, hits on the perfect kind for Monk to wear as a buttonhole: a plastic one from a pen.