Roses are a little difficult to understand. The color of roses is meant to symbolize various things.
However, having had little experience as the recipient of roses, I can only surmise according to my experience.
1. boyfriend comes home with 1 or 2 roses: means boyfriend was out with another girl, stopped at the store, bought a couple roses, and is silently apologizing.
2. guy and girl stop at the gas station, guy buys one of those roses wrapped in plastic: means the guy can afford an extra dollar or two to buy something cheap for the girl.
If it is the same girl as in scenario one, girl is now suspicious about the guy.
3.coworker brings dying homegrown roses to girl. Girl realizes coworker is making a very cheap attempt to impress her.
4. girl without boyfriend finds cheap rose wrapped in plastic nonchalantly placed somewhere in her residence. Girl is not sure if she would be considered as paranoid if she wonders where the rose came from, and knows that the police wouldn't understand.
5. girl's friend receives a dozen roses from boyfriend, and another dozen roses from same boyfriend the next day. Friend is bragging, friend's boyfriend is loudly apologizing.
6. girl's coworker receives live miniature roses from husband for Valentines Day. No explanation necessary.
well, that about sums it up. I prefer carnations, anyway.