It sounds like you've made up your mind that you really want to do this, so maybe it doesn't matter what others think. I have only seen flowers in my therapist's office twice in 3 years. One was clearly from a significant other and the other was from "someone" (her word) who had grown them. I understood the "someone" to be another client but I can't know. I do think bought flowers assume a certain intimacy that is outside of the therapy relationship. Picked flowers, less so.