Trim Rose bush
http://extension.oregonstate.edu/mg/metro/sites/default/files/Rose_care.pdf Thanks for your question about roses! The short answer is "yes, you need to prune your rose bush.' I'm guessing that you didn't get many blooms on it, because the blooms are only going to happen at the end of the stem--and you have only one stem!
Roses are woody (with bark) perennials (they live year after year), and when you prune near the bottom of the plant, new stems branch out, so the bush is fuller and more productive bloom-wise.
Here's an Extension publication you can go to (see page 2) about why and when to prune. You won't have some of the issues mentioned (since you have only one stem), but in a few years, hopefully, you'll have a beautiful rose bush plant!