I guess I'm not a manly-man like some who posted in this thread.
I give friends with benefits flowers all the time. I also give them to my mom. To my girlfriends' moms. To female friends. And to male friends (some gay, some not) who appreciate them. It's a little token that says I give a shit about them. Sometimes its a pick-me-up. Others its as a host(ess) gift. It's no big fucking deal and I make that abundantly clear. Flowers just happen to be something nice that people like.
(One caveat: I don't give flowers to FWB on Valentine's Day, birthdays or occasions unless they're having a rough time - and then I'm clear that it's because they're feeling blue or whatever...)
Only insecure losers overthink shit like this. I think that's why so many on here are unable to have a real relationship with women.
I am the same way with flowers. I have a florist on speed dial. But I don't give my dentist flowers. There are appropriate gifts for certain relationships and giving flowers to a FB can imply something not there. Better to be safe and go with a more appropriate gift.
You even said yourself that you don't give flowers on certain occasions. I am assuming that it is for the same reason.
Also with the amount of flowers you give, you may be better equipped like me, to know what type of flowers to give for certain relationships, meanings, occasions etc. As well as you should know how some other people can perceive getting flowers. Many other may not know this.
Since this was such a general question and we know nothing about the girl involved, I think going the non-flower route is best. That is just my personal opinion however. As a female, who has been a fuck buddy a time or 10. LOL