It is not a secret that women are fond of flowers. Men do know about it but many of them don't give flowers to their ladies or do it anonymously through a flower delivery service. Why? There may be some reasons and one of them is that men often don't know what flowers their ladies like. So, they are afraid that a lady won't like the flowers and therefore won't appreciate their attention. One should understand in this case that it is not necessary to follow standard rules and give, for example, purple flowers to the red-haired lady as it is written in books even if she hates them.
First of all, try to find out what flowers the lady likes. Sure, you don't have to ask all her friends about it, you can just present flowers every day, look at her reaction and make some conclusions.
One day when you give the lady's favorite posy to her you will see her pretty smile and happiness in her eyes.