Concern about rose bush
This does not look like rose rosette. The rose looks like it needs some maintenance. You did not mention the type of rose or any controls you are using. Roses are susceptible to several fungal diseases such as black spot, cercospora, powdery mildew, stem cankers, as well as pests such as rose slugs. http://extension.umd.edu/hgic/rose-slugs-shrubs
Roses are not that easy to grow in our climate. With all the wet weather that we have been experiencing it can be difficult.
All you can do is monitor for diseases and insects, keep up with a spray schedule if using, and practice good sanitation. Prune dead canes back to healthy wood.
You may want to look at our rose publication and pruning for general information http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/non_HGIC_FS/EB164.pd...
Thank you! It's a relief that you don't think it's rose rosette disease. It is a pink knockout rose, and I selected it because it is supposed to be more disease-resistant than many. I stay away from much that would splash water on the foliage, and grow ground cover instead. I use only organic or non-toxic methods, which makes it more challenging but rewarding as well.
Here is a good page on knock out roses. http://extension.umd.edu/hgic/rose-rosenot-always-look-%E2%80%98knock-out%E2%80%99-landscape-roses