These roses are beautiful. I seem to like the way the smaller one on the right is 'looking' up to the larger rose. It looks a bit like some type of parent/child relationship in this photo.
Photographing flowers is something that I'm not very experiences with at this point. I have been doing some recently and I have learned a few techniques that seem to help create some higher level of impact in the photos.
Taking the photo outside is a great idea because your lighting will be natural and the issues of color cast and white balance will not play a large role in the photo. I made THIS PHOTO over the weekend outside on my back porch. I used a piece of black posterboard behind the flower to get the dark background. I angled the posterboard in such a way that it would be 'shadowed' to get the nice dark effect. You can try things like this with your roses also... The wind can be a problem, so it may be a good idea to look for opportunities to avoid that.
Another important element, in my opinion, is a tripod. I always use my tripod for photos like this and let my timer take the photo to minimize camera shake. That also frees my hands to hold the posterboard behind the scene :)
Where I work, I see a lot of different images of roses. Generally they are actually drawings, but the colors and the actual flowers never look this nice :)
The direct lighting on top of the flower makes it look bright and pretty. It makes me wish the direct light was somewhere in front of the whole picture, though, so that it brightened the whole bud. I like that there's two buds, but the background color lets the green show too much and the plants behind are distracting.
Wow, beautiful! You've managed to get both flowers fully in focus although there is a distance between them, and then you were able to blur the background, well done!