First off, I don't know much about roses at all. I'm planting an entirely edible landscape in a Tudor style, and after reading that all Rosa species flower petals are edible, I decided I had to have one! It's a little trickier than that though... the whole landscape is also evergreen, or at least semi-evergreen. I haven't found any definitive answer as to whether or not there are any roses that would be at least semi-evergreen in MD zone 7. I'd prefer a rose that's thornless, or nearly thornless. And of course, since it's for an edible garden, a fragrant flower would be a huge plus (most edible flowers taste like they smell). The growth habit doesn't matter too much, though something substantial would be preferred.

What a cool garden plan!
Any of the rugosas as would work well, I think, because the texture would complement the conifers in the winter, and the hips would add color. The rose hips are edible by humans, with preparation, and surely the petals would taste as good as they smell. Maybe someone else can suggest a rugosa that is thornless. There may not be such a thing, though.

Cindi ... Linda Campbell is almost thornless.

There are thousand and thousands of roses that are evergreen. The evergreen gene came into the rose gene pool when the repeat blooming gene was introduced to the rose gene pool. Narrowing it down is what becomes difficult.

Roses are in the same plant family as apples.

Mike, I've been thinking about your question and thought you might want to look at your rose plants a bit differently that the rest of your garden plants. Rose hips are the fruit of the plant. They provide the most beautiful winter interest and come in so many different shapes and forms. Some are bright red. Some come in clusters. Some are small. Some are quite large. Many can be used for medicinal uses. Some are used to make preserves, so it's not just the petals that can be edible or use for perfumes and sachets.

Roses can add structure to your garden and provide nesting places for birds and more. So think beyond rose petals and you will find that will help you define the rose you are seeking in less general terms.

I did a quick Google search for "culinary uses for rose hips" and got a lot of hits. I think you should start your own search there.