Question
We have 10 rose plants, and one suddenly looks like no rose
i've ever seen!  after pruning a few months ago, while the
others grew back normally, this one is stunted, maybe 10-12
stems growing straight up from the underground rootball,
from 4 to 10 inches high with tiny, i mean tiny, leaves, a
few teeny buds with sickly looking petals that didn't round
out.  i've called it the mutant...but i'm concerned that it
might spread, the plant won't come back to  it's former
state, and i might not successfully plant a new plant in
it's place.  we've used a bayer rose disease product for a
few years, and recently my husband used some organic
pesticide (for tomatoes!) made with sesame oil and fish oil.  
But the other roses are ok.  help!

Answer
From your description, it sounds like your rose has a virus problem. This can cause weird growth pattern in a rose. I would dig it out and get rid of it. The virus will not be in the soil so you can plant another rose in the same hole. The virus will be unique to that rose and will not spread to any other roses or plants. There is no cure for virus.