Ohioguy wrote:

http://s9.postimg.org/7xum08afz/rose_spots.jpg

I planted 6 rose plants almost a month ago, and all of them seem to
be growing fairly well.

However, 1 of the plants has yellow spots on it. Most of them are on
the lowest leaves, but I believe there are also a few of these on 1 or 2
of the newest leaves.

Is this some disease that I need to be worried about?

Those yellow splotches look like the leaves were splashed with
fertilizer, or some kind of chemical... could even be overspray,
perhaps from a neighbor.