This is very often overlooked but in my opinion the right URL structure is critical for any site, because the on site optimisation and content creation for landing pages will be very much determined by the structure of your URL's. Logical structure also helps users understanding and navigating the site.
I always suggest a "library" approach, so creating a logical structure similar to a library where a book (or a product/service/article etc.) falls under one parent category, which falls under a higher parent category, similar to:
science-books/physics/newton-inventions
entertainment-books/childrens-books/harry-potter
I your case the first example of URL path makes more sense, but the question is - are dozen roses only anniversary flowers? Spend a few hours organising your products into categories that make logical sense and create a URL structure to reflect that but keeping in mind the keywords people are searching for to find your products. It's not easy so don't rush it.
Ah and use hyphes (-) rather than underscores (_) in your urls...
