I have well established roses in my garden. This year, a couple strange rose bush looking plants started growing right next to one of my rose bushes. The yellow rose bush has been blooming (some) but hasn't flourished like it should, while these strange bushes next to it that look like a rose bush have not had any flowers, just long gangly thorny stems which I've been trimming back all summer. Their leaves look slightly different from the yellow rose bush as well. Looking at the bases of them they don't seem to be associated with the yellow rose bush either but know sure what is happening underground.

Does anyone know what these might be? Should I get rid of them? And how?

Thanks!