Personally I don't do flowers with girls who are not in a LTR with me. Even then, I rarely get any. My advice would be against it, but then again I don't know the girl. If she's the corny type she'll like it.
Tell her something like "I want a cute and smart girl to spend V-day with." *3 seconds of eye contact in silence, smile.* "...do you know any?"
She'll think you're asking her out at first, but the follow up should get a laugh. Do what you need to do to get her on V-Day, I have a feeling that after her vacations your chances will be very much smaller if you don't.