Sorry. It's hard to judge if someone's really gonna like flowers or not, especially since pollen allergies aren't all that uncommon.

[Let her be a little more cheerful about this.]

Flowers are a good start though! Even the roughest girl I know would appreciate them (I think, don't quote me on that, she really seems like she likes nature) and if you want to start out on that, then I say go for it. Just don't do anything overly romantic, like an entire bouquet of red roses. Even I'd be embarrassed to get that from anyone.