"Lady Of The Flowers" is a song from Placebo's first album: "Placebo".
Rumor has it that Brian mentioned in an interview that the song is actually about a transvestite however he has a fairly twisted sense of humor and so could have been joking.
It makes sense for it to be about a transvestite as early in the song the subject is referred to as a "he" while later they are referred to as a "she".
Some parts of the song that can be interpreted in this way:
"he spends the afternoon, between your thighs
how's that for gratitude, I apologize."
-- I think here it is about being ungrateful for the male anatomy he was given (between his thighs) and is sorry for not being happy with it (I apologize).
"she's got vacum cleaner eyes
suck you in"
-- could be a reference to the subject making people believe that they are a female (suck you in) when she was originally a male.
"She wears her tears on her blouse
confused and racked with self-doubt
she stole the keys to my house
and then she locked herself out"
-- He/she is not sure if they made the right decision and is perhaps ashamed of what they have done (racked with self-doubt). By becoming a transvestite it is possible that they are no longer accepted by their family (locked herself out).
"She lays me down
she lays me"
-- I'm not sure about this part but it could be a reference to leaving her male life behind her and moving on.
In saying all this, it is entirely possible that this song is nothing to do with a transvestite and Brian was joking when he said it.
The thing about song meanings is that the actual meaning of the song (when it was written) becomes irrevelant when you listen to it. It loses the personal meaning when it is released and instead of being Brian's story, it becomes the listener's story. You can interpret it any way you like, and you will be correct because you will relate it to something else as it becomes your story.